Tag Archives: dry screw

China Good quality 250kw Variable Speed Drive High Efficiency Silent Industrial Screw Rotary Oil Free Dry Two Stage Air Compressor mini air compressor

Product Description


   Specification(VSD series)
  Model Capacity M3/min Power kw Noise level db Weight KG
3.5~10bar Water Cooling  Air Cooling
OFA1VSD OFA15VSD 1.1-3.3 15 74   930
OFA22VSD 4.5-5.6 22 74   1150
OFA30VSD 4-6.6 30 74   1300
OFW37VSD 5-8.4 37 74   1600
OFW45VSD 6.1-11.1 45 74   1750
OFA2VSD OFA55VSD 7.3-9.4 55 74   1900
OFA75VSD 10.7-12.4 75 74   2630
OFA90VSD 12.7-15.4 90 74   2700
OFA3VSD OFA110VSD 16.0-19.5 110 74    
OFA132VSD 18.8-21.8 132 74   4300
OFA160VSD 24.0-29.6 160 74   4300
OFA4VSD OFA200VSD 12.2-36.6 200 74    
OFA250VSD 14.2-41.8 250 74   6950
OFA275VSD 15.8-47.4 275 74    
OFA315VSD 45.0-52.1 315 74   6950
OFA5VSD OFA355VSD 50.4-57.5 355 74    
OFW1VSD OFW37VSD 2-5.9 37 74    
OFW45VSD 2.3-7 45 74    
OFW2VSD OFW55VSD 4.5-8.8 55 74    
OFW75VSD 4.5-13.2 75 74 2170  
OFW90VSD 4.5-15.5 90 74 2220  
OFW3VSD OFW110VSD 6.4-19.1 110 74    
OFW132VSD 7.7-22.4 132 74 3500  
OFW160VSD 14.5-42.9 160 74 3500  
OFW4VSD OFW200VSD 18-36.1 200 74    
OFW250VSD 19.-38.4 250 74 6400  
OFW275VSD 20.0-41.0 275 74    
OFW315VSD 46.0-50.9 315 74 6650  
OFW5VSD OFW355VSD 50.4-56.3 355 74 6950  
OFW400VSD 55.8-62.1 400 74 7060  
OFW450VSD 63.8-76.5 450 74 8400  
OFW500VSD 73.1-83.9 500 74 8400  
OFW630VSD 89.0-102.9 630 74 9125  
OFW750VSD 101.8-122.8 750 74 9225  

Company Profile

       ZheJiang Napu compressor Technology Co.,LTD was established in 2012  based in ZheJiang ,specializing in oil-free rotary screw air compressors, offering a wide range of products from airends to compressors . 
       With over 10 years experience in oil free screw air compressor. NAPU Compressor is compliant with ISO 8573-1, Class 0 standard and audited by TUV Rheinland and China National Quality Inspection Center of Compressor and Refrigerator.   
        The company is also compliant with ISO 9001:14001 and is CZPT in the domestic market for its quality-driven culture. The oil-free compressors manufactured by the company are used in a variety of sectors including some of our valued clients like CASC-China Aerospace Science Corporation, NORINCO-China North Industries Group, CNNC-China National Nuclear Group, CHANG AN AUTO, SINOPHARM, BYD and CALT and Sino-Chemical etc.
         Continuous improvement in productivity and efficiency is our goal, and we continue to offer an extensive services including our own branded oil-free compressor package as well as after-sales services for other leading brands.


Product Features

1. In house designed airend
2. 100% oil free air certified by Germany TUV.
3. Double-layer structure to reduce he noise.
4. Air Cooling and Water cooling are available.
5. VSD control are available.
6.Touch Screen PLC with preset running schedule, more intelligent control.
7.OEM&ODM service are accepted



Q1. Are you trading company or manufacture ?
A: We are professional manufacture of oil free air compressors. More than 20 years of experience in air compressor manufacturing.
Q2. What’s payment term ?
A: T/T, Western Union, Paypal, Credit Card, and etc. Also we could accept USD, RMB, Euro and other currency.
Q3. How about your after-sales service ?
A: 1.We can provide customers with installation and commissioning online instructions.
Q4. How about your warranty?
A: One year for the whole machine and 5 years for screw air end, except consumable spare parts.
Q5. Do you have any certificate ?
A: Yes, we can offer CE ,ISO  and certificate as clients’ demande.
Q6. How do you control quality ?
A: 1. The raw materials are strictly inspected
    2. Each compressor must pass at least 8 hours of continuous testing before leaving the factory.
Q7.How long could your air compressor be used?
A: Usually, more than over 10 years.

After-sales Service: Online Support
Warranty: 12 Months
Lubrication Style: Oil-free
Cooling System: Water Cooling
Power Source: AC Power
Cylinder Position: Horizontal



Choosing an Air Compressor

Considering a new Air Compressor? Here are some tips to make the decision easier. Learn the pros and cons of each type, including the differences between oil-injected and oil-free models, single stage and positive displacement. In addition, learn more about the different technologies that are available for your air compressor. It is important to choose an appropriate unit for the type of work you do. Here are some of the best compressors available today.

Positive displacement

There are several different types of air compressors, but most are positive displacement air compressors. They use a rotary or reciprocating component to compress air. The reciprocating component compresses air by reducing the volume of the chamber. Positive displacement compressors are used in bicycle pumps, chemical plants, and refrigerators. Positive displacement air compressors use multiple inlet ports. Despite the various types, the principle of operation remains the same.
Another type of positive displacement air compressor is a reciprocating piston. The piston inside a cylinder moves up and down, causing the compressed air to fill the upper part of the cylinder. These air compressors are used in a variety of different applications, including blowing bottles and gas pipelines. These air compressors can be water-cooled, lubricated, or non-lubricated. Different types have different capacities and air pressures.
A positive displacement flowmeter uses a rotating chamber that divides continuous fluid into discrete portions. The number of times the chamber is filled and discharged can be used to estimate the flow rate. The rotation speed of the measuring chamber is directly proportional to the flow rate. The drawbacks of this type of positive displacement flowmeter are that it is prone to jamming. If the fluid contains particles, it may be too thick for the meter to determine flow rate.
A negative displacement air compressor was invented in 1860 and is the oldest type of compressor. It uses two lobes positioned in a circular cavity. One rotor is connected to an engine, while the other pushes the other one to spin in the opposite direction. Negative displacement compressors are low-maintenance, but they do require more precision. They are often used in nuclear power plants because they use the kinetic energy of the rotating elements to produce pressure.


Oil-flooded or oil-injected air compressors use liquid to seal and lubricate moving parts and reduce noise. Oil-flooded air compressors are effective for a variety of pneumatic tools and accessories. Some models have a thermostat that controls the amount of oil used during operation. Other types of oil-flooded air compressors are piston-type models. Here is an overview of the basic differences between these two air compressors.
An oil-injected air compressor is more expensive than a comparable oil-free air compressor, but its advantages far outweigh its disadvantages. An oil-free compressor is quieter, requires less maintenance, and has a lower price tag. It also offers a greater degree of air purity. A number of other advantages may also make this type of air compressor the better choice for many industrial settings. If you need a high-pressure compressor in a tight space, consider the benefits of an oil-free system.
Oil-injected air compressors require more maintenance than oil-free models. Both types of air compressors offer similar capacity and ISO 8573-1 Class 0 and 1-2 purity, but the oil-injected systems require more air-treatment components. They require an activated carbon filter and coalescing filter. Oil-injected air compressors will likely remain the standard for industrial air compressors for many years. And since their performance and efficiency are comparable, it may be worthwhile to invest in some point-of-use air treatment.
Both types of air compressors have their benefits. However, choosing between oil-free and oil-injected air compressors is not as straightforward as you might think. Whichever type you choose, make sure it will meet your needs. The benefits of an oil-injected air compressor outweigh their disadvantages. In general, oil-injected air compressors are more durable and can last longer than oil-free models. The only downside is their higher price.


When choosing an air compressor for your company, you’ll need to determine what it is going to be used for. For example, if you’re planning on using it to power multiple workers, you should consider getting an oil-free compressor. An oil-free compressor, on the other hand, is quieter and can power several workers at a time. If you’re a contractor, the most important consideration will be the type of jobs you’ll be doing. Higher air pressure means greater demand for air flow, and more pressure can damage the equipment.
Oil-free compressed air is certified 100% free of contaminants. Technically, oil-free air is not completely free of foreign matter, but it is extremely low within the limits of practical air quality. A technically oil-free air compressor might have a total oil level of 0.003 mg/m3. If you’re in need of a technically oil-free air compressor, you must install an air treatment equipment after your current compressor.
If you’re in the manufacturing industry, a good oil-free air compressor will save you money and reduce your environmental impact. Many of these tools require air compressors to work, and this equipment will ensure that they don’t get contaminated. To buy the best oil-free compressor, you should learn a bit about the different terms used by compressor repair companies. ACFM, for example, is the amount of air that can be compressed in one minute at rated conditions.
When you’re using an oil-free air compressor, you should know that the overall life of the device will be much shorter. Compared to an oil-flooded rotary screw air compressor, an oil-free compressor typically has a lifespan of 50 thousand hours. But it’s important to understand that this type of compressor can still cause damage to piping and processes. Therefore, you should choose an oil-free compressor when you need to clean air for your business.


A single-stage air compressor, also known as a piston air compressor, compresses air only once before storing it in a cylinder. This stored air has enough energy to power a variety of pneumatic tools, such as screwdrivers, chisels, and wrenches. These units are also ideally suited for low-flow applications and are widely used in gas stations, auto shops, and various manufacturing plants.
A single-stage air compressor uses two valves – one for inlet and one for outlet – to transfer compressed air. Both valves are actuated by springs. The inlet valve has a slight curvature to provide protection from damage. The compressor’s outlet valve opens when the pressure in the cylinder is higher than the pressure in the storage tank. The piston moves very quickly inside the cylinder, exerting a high amount of force throughout the compression process. This high piston speed is a common cause of compressor wear and tear.
A single-stage air compressor is ideal for smaller tradesmen and small construction crews. Its lightweight and compact design make it easier to transport and store. While it may be tempting to buy the first cheap air compressor you see, it’s important to balance the price against performance to choose the right air compressor for your needs. The best single-stage air compressor is one that provides excellent performance and durability. Its two-stage counterpart is designed for larger construction teams and large applications.
The main difference between a single-stage and a two-stage air compressor lies in their capacity. A single-stage air compressor compresses air only once and delivers it into the storage tank, while a two-stage compressor compresses it twice, creating double the pressure. Because of this, single-stage air compressors are cheaper and versatile than their counterparts, which means that they can be used for multiple purposes.


A low-noise air compressor is a type of industrial compressor that is less noisy than regular air compressors. These are generally smaller machines designed for smaller factories and workshops with a few to several employees. They are designed to handle mid-weight volumes of compressed air per day. This type of compressor is especially useful for smaller manufacturing businesses that need to produce compressed air for medical applications. Small breweries can also benefit from the low-noise capabilities of these compressors.
Low-noise air compressors come in various sizes and features. For smaller jobs, you can purchase a one-gallon model that is lightweight and portable. For larger jobs, you can purchase one with a larger tank that can provide more pressure for longer jobs. However, a larger tank will make the compressor heavier and harder to transport. To avoid this, make sure to check the size of the tank and how much power it can handle.
Considering a low-noise air compressor for your business? If so, you’ve come to the right place. There are a variety of affordable and dependable low-noise options to choose from. A CAT 10020C, for example, is designed to provide high-volume air to many outlets at once. A CAT 10020C comes with a 10-gallon tank, wheels, and a carrying handle.
Noise levels can also affect the productivity of employees. When employees work with air compressors in close proximity to each other, they may develop tinnitus. If employees are free from tinnitus because of the loud noise, they are likely to work more efficiently. Moreover, it will be easier for them to focus and communicate efficiently. If you need a compressor, a low-noise one is an excellent choice.

China Good quality 250kw Variable Speed Drive High Efficiency Silent Industrial Screw Rotary Oil Free Dry Two Stage Air Compressor   mini air compressorChina Good quality 250kw Variable Speed Drive High Efficiency Silent Industrial Screw Rotary Oil Free Dry Two Stage Air Compressor   mini air compressor
editor by CX 2023-05-16

China factory “Great” 110kw/150HP Water CZPT Dry Type Oil-Free Double Screw Air Compressor, 0.75~1.05MPa wholesaler

Solution Description

The Fantastic Oil-Free Double Screw Air Compressor there are diverse models to choose from: the motor electrical power from 55kw to 355Kw, the operating force from .75Mpa to 1.05Mpa, the circulation potential from 8.0m³/min to 58.4m³/min. We can also customise in accordance to your wants. This variety of air compressor is suited for the sector which require really substantial-good quality compressed air.

A. The Picture for Oil-Free Double Screw Air Compressor:

B. Goods Introductions & Benefits for Oil-Free Double Screw Air Compressor:

Oil-totally free compressed air is utilized to all walks of life which have a serious effect on the ultimate product and manufacturing process, these kinds of as aerospace, spraying, foods and beverage, pharmaceutical, petrochemical, semiconductor and electronic products, health-related, automotive spray, textile, and so on. In these harsh purposes, even tiny quantities of oil can cause poor goods to show up and even quit production. Above the earlier 10 years, the Wonderful compressor has been checking out the advancement of oil-totally free compressed air technology, and has introduced a variety of oil-totally free air compressors to give one hundred% pure air for clients. Through continuous analysis and improvement, the Fantastic compressor has CZPT a new HangZhoustone, turning out to be the company of the Class certification, which defines the new normal for the purity of compressed air.

The features of oil-free of charge screw air compressor:

1. The air high quality of the secure and oil-free is strictly based on the ISO 8573-1 Class (2571) standard, and there is no compromise on the closing compressed air purity, making sure the air pollution-totally free chance.
two. The CZPT imported air conclude, big rotor, minimal speed, comprehensive device functionality is outstanding. Rotor by the dynamic and static stability take a look at strictly, make it perform much better balance, considerably less vibration, reduced sounds, at the very same time under the problem of the same diameter, the size of the rotor boosts, effective compression quantity enhance, so as to accomplish site visitors boost, reduce electricity consumption.
3. Bearing: in order to make certain the bearing to bear substantial velocity and large load, the screw compressor adopts the high-top quality bearing of CZPT manufacturer, which retains the long bearing lifestyle.
four. The shaft seal gadget: the double ring fluorine rubber ring with steel frame can with stand specific pressure to form a lubricating shaft sealing device. The linings on the shaft are specially processed by our firm, with best sealing overall performance and long provider existence.
5. Systematic layout: the technical personnel to the system optimization design and style to make the unit operation fault tremendously decreased, the air volume is more secure, energy consumption than the superior ranks of the peers.
6. The total machine is made with reduced noise.

C. Ingredient Details for Oil-Free of charge Double Screw Air Compressor:

D. The Technical Parameters of Oil-Free of charge Double Screw Air Compressor:

E. Apps:

F. Certification:

G. Packing:

H. Firm Profile:

I. Our Services:

1. Following-sale Support
    1). Any queries or requests ahead of, during or following sales, we would like to help you any time and will discover you the very best answer in 24 several hours.
    2). Guarantee: One particular calendar year for the total equipment 2 12 months for air end , and spare parts will be presented with ideal cost.
    3). Over board engineer service is accessible.

two. Particular Custom-made Support
    1) Complete OEM
      • Quantity: at minimum 5 pcs
      • In this program, we will do all the changes (Color, identify plate and symbol) as your want, and will not cost additional price.
    2) 50 % OEM
      • Amount: no limit
      • Under this plan, we can make the needed alteration (identify plate and logo) but we will demand some added fee for the identify plate, as the identify plate manufacturing facility has the MOQ.
    3) Symbol OEM
      • Quantity: no restrict
      • Only the symbol will be modified to yours, and no added price will be charged.

3. Abroad Engineer Services
    We are accessible to send our engineer for aboard support. Only need to have you to arrange the accommodation, transportation and translator. Added expense for every will be reviewed based on regional cost degree.


Q1: Are you factory or trade business?
A1: We are factory. And we have ourselves buying and selling company. 

Q2: What the precisely deal with of your manufacturing facility?
A2: Our firm is positioned in the West of the CZPT of Yijing road and Siwei street, Xihu (West Lake) Dis.li Financial Growth Area, ZheJiang , 300300, China

Q3: How about the guarantee terms of your device?
A3: One particular calendar year for the whole equipment and 2 a long time for screw air finish, and specialized assist according to your wants.
Q4: Will you provide some spare elements of the machines?
A4: Indeed, of system.
Q5: What about item bundle?
A5: We will CZPT the products strictly with regular picket carton.
Q6: Can you tailored the voltage of items?
A6: Sure, the voltage can be tailored in accordance to your prerequisite.

Q7: How extended will you get to prepare generation?
A7: 380V 50HZ we can delivery the merchandise inside 7-fifteen times. Other electricity or other coloration we will shipping and delivery inside of fifteen-20 days.
Q8: Which payment term can you take?
A8: T/T or L/C.
Q9: Which trade expression can you settle for?
A9: Available trade terms: FOB, CIF, CFR, EXW, CPT, and so forth.

Q10: Can you use our model?
A10: Yes, with professional design and style team, the OEM orders are very welcome.

What to Look For When Purchasing an Air Compressor

An air compressor is a very beneficial resource that can assist you comprehensive a lot of various types of construction jobs. This useful equipment can make numerous jobs a lot less complicated, but not all of them are developed equally. Knowing what to look for when buying an air compressor will help you make an knowledgeable choice. Listed here are some of the factors you must search for. These consist of price tag, measurement, and strength performance. Also, make confident to take into account the air compressor’s kind.

Solitary-phase air compressors are quieter

When it comes to noise amount, single-stage air compressors are the way to go. These devices have much less moving elements and are quieter than two-phase types. Solitary-phase air compressors use an axial circulation style and can be quieter than their twin-phase counterparts. Single-stage air compressors can operate for a longer time and at lower pressures. Single-phase air compressors can be employed for gentle industrial applications. They have a extended lifestyle expectancy, with some models lasting for over three thousand hours.
Even though some one-phase air compressors are quieter than two-phase air compressors, both versions have sound-reduction characteristics. 1 type characteristics rubber parts, which are created to dampen noise. An additional function can make a compressor quieter: its spot near the task web site. Some designs function rubber foundation plugs and rubber mats to lessen floor vibrations. In addition to utilizing these attributes, single-stage compressors are less complicated to transportation.
Noise stages are critical when selecting an air compressor. Some devices are too noisy for comfy operate, and some companies will not want to expose clients to sound-creating air compressors. Other noise ranges can even endanger workers’ wellness. Solitary-stage air compressors are far more reasonably priced than twin-phase compressors. They are also quieter and a lot more effective. But be well prepared for the sounds. Some solitary-phase air compressors are still noisy.
Compared to their two-phase counterparts, one-phase compressors are quieter when operating at entire capability. However, double-stage compressors are quieter on minimal capacities than single-stage units. People with variable pace are quietest at reduced capacities. The variation is about 10db. If you are worried about the noise degree, you must think about a two-stage air compressor. But if you have a small workshop, it may not be suited for you.
A single-stage air compressors are typically far more productive than two-phase air compressors. The noise from a two-stage air compressor is reduced because there is certainly no intermediate phase. Solitary-phase air compressors also use a piston that rotates in a one stage, although twin-phase air compressors, also recognized as duplex models, are a lot more efficient. A one-stage air compressor is quieter, but double-phase compressors are louder.

Two-phase air compressors are much more power productive

Two-stage air compressors are much more strength-successful than single-stage equipment. The performance of two-stage air compressors is elevated through a blend of improved effectiveness and enhanced longevity. These devices can keep far more air and have larger compression ratios. 1 product of a two-phase compressor can keep roughly 83 cubic toes of air at one hundred PSI and one hundred twenty cubic ft at one hundred fifty PSI. A two-phase compressor is also quieter.
Two-phase air compressors are far more vitality-successful simply because they have two pistons as an alternative of one particular. These air compressors attain a greater force score and get better far more rapidly. This variety of compressor is best for positions that call for substantial air stress for a extended period of time of time. In addition, they can work several equipment simultaneously. This makes them better for industrial and industrial use. Outlined under are some advantages of two-phase air compressors.
Solitary-phase air compressors can energy resources in the garage or kitchen area, but they are not as reliable for industrial apps. Solitary-phase compressors have larger components that have a tendency to expertise condensation. Additionally, solitary-stage compressors do not final lengthy in constant use and are less vitality-efficient than two-stage ones. Whether or not you are utilizing the compressor for a solitary tradesperson, a little crew, or a huge development crew, two-phase compressors are the greatest decision.
One-stage air compressors are usually utilised in small-scale foods planning and generation. One-stage air compressors are simple to transport in between locations, and can be plugged into a number of electrical outlets. Single-phase compressors are also excellent for substantial-volume foods processing. A dual-phase air compressor is best for industrial use. In some instances, you can even go the solitary-stage air compressor in between two-phase air compressors.
Single-phase compressors frequently cycle also speedily, drawing more electric power than two-phase models. A variable pace device stays on a low pace for hrs at a time. Single-phase air conditioners drive you to lower your thermostat settings although single-stage air conditioners run also usually. Both units are power-effective but they are not as power-efficient as variable-velocity compressors. The principal distinction is that solitary-stage air conditioners are inclined to drain the energy resource a lot quicker.

Piston-pushed air compressors are quieter

A piston-pushed air compressor is a single of the quietest types of air compressors. It is much less noisy than reciprocating air compressors. A piston-pushed air compressor can attain sixty two decibels, even though a scroll compressor is all around fifty percent that quantity. The two principal components of a scroll air compressor are the piston and the helical screw. These air compressors are each really efficient and tranquil.
More mature compressors are exceptionally noisy. They create a “wumpa” sound related to a large motor. They are also able of generating a higher-pitched whine. These noises can be deafening, particularly in a modest workshop. That’s why it is important to search for a tranquil compressor. But what tends to make a compressor silent? Read on to learn more about this crucial instrument.
Yet another distinction in between piston-driven air compressors and electric-driven air compressors is the power resource. Electric powered air compressors make less sounds than gas-driven compressors, which use an engine. Piston-pushed air compressors are also more successful. They also generate considerably less heat, producing them an best selection for offices and other configurations the place sound is a difficulty. The ideal way to determine in between the two kinds of air compressors is to examine the manufacturer’s guarantee and study the ‘Description’.
Noise reduction is the initial priority of a compressor’s owner, so make certain that you have the proper model. If you might be functioning on one thing delicate, never area the compressor way too near to a building in which people may well be close by. Sound can be very disruptive to the workspace and can trigger overall health problems. To assist overcome noise, you may require to acquire a quiet air compressor. And don’t forget to consider its location: Piston-pushed air compressors are quieter than their reciprocating counterparts.
Piston-pushed air compressors are quiet due to the fact the piston is made of slender metallic and more rubber, which absorbs the sound. In contrast to reciprocating air compressors, piston-pushed air compressors are more productive than their dual-piston cousins, which are quieter and far more effective. So which type is right for you? Take a look at some of the principal differences in between the two. If you want a quiet compressor, make sure it satisfies the requirements required by the occupation you are operating on.

Oil-lubricated air compressors are far more value-efficient

There are a number of causes why oil-lubricated air compressors are much more high-priced than dry-variety air compressors. First of all, oil-lubricated air compressors tend to be a lot more dependable and quiet. In addition, oil-lubricated air compressors call for fewer elements and can previous lengthier than dry-variety air compressors. These are just a handful of of the several benefits of using oil-lubricated air compressors.
Oil-free air compressors have some down sides. They are much less sturdy and may not be as successful as oil-lubricated types. Additionally, because oil-lubricated air compressors use oil, they can get quite noisy. While they are significantly less high-priced, they are not the best choice for heavy-responsibility work. Nevertheless, modern oil-free of charge air compressors have soundproofing and are ideal for industrial use.
When buying an oil-lubricated air compressor, make confident to decide on a single with a tank ability that fulfills your wants and your room. Bigger tanks can be more expensive than modest tanks, but greater models are simpler to move about. Also, be positive to contemplate the weight and dimension of the transportable air compressors when making your decision. If the bodyweight is also massive, you may possibly have difficulty carrying it from place to place.
Another benefit of using oil-lubricated air compressors is their reduced need to have for oil. These types can previous up to a 10 years for a longer time than oil-free of charge counterparts. Oil-free air compressors are more inexpensive and can accomplish the same high efficiency as their oil-lubricated counterparts. Several industrial purposes advantage from these air compressors. So, which one particular is appropriate for you? We’ve listed a few of them under.
One more benefit of deciding on an oil-lubricated air compressor is the reduced price of upkeep. This sort is a lot more sturdy than its oil-lubricated counterparts, which require normal oil modifications to hold them running smoothly. Nonetheless, it is not possible to transport an oil-lubricated compressor, which indicates that you have to set up it permanently to preserve it working successfully. In addition, these air compressors are tough to move and are not portable, which can restrict your capability to use it in a pinch.