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Availability:
Only 1 left in stock, order soon!
Arrives
Wednesday, Oct 21
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Features
- GX Patented Design :GX features an exclusive four-stage compression system paired with an integrated water-cooled compressor structure, powered by an genuine 350W high-performance motor. It is very stable when working, and it is very quiet with only 70db. At the same time, it is equipped with a double-pointer pressure gauge, and the two-level setting auto-stop pressure, which is more secure. This distinguishes it from others, which merely add water circulation devices to small shoebox-style compressors on market.
- A water tank and a grease tank are designed on the top of the airgun compressor. The excellent cooling can achieve 5 hours of continuous work . Note: For the first use, it must be filled with neutral distilled water or antifreeze ( PH is about 7). Note: 1) you can only add antifreeze if it freezes in your area in winter. 2):Do not turn the grease knob until after 6 hours of use, otherwise will cause bad performance. then turn it one turn every worked for 6 hours. The new version now includes a hour meter.
- 15% Faster Filling Speed: Filling 0.5L Airgun or Paintball tank from 3000Psi to 4500psi ,only needs 4-5 minutes. Filling 0.5L from 0-4500psi, only needs 14-16 minutes. but filling 6.8L bottle from 0-4500psi ,will need 2 hours and 40 minutes . Notice: CS4 and CS4-I are mainly used for high pressure, small gas cylinders below 6.8L, especially PCP. It is not recommended to fill large gas cylinders. Otherwise, you can choose 5K1 and 5K2.
- Built-in 110v to 12V DC Converter: Compared to the GX E-CS4, the CS4-I has a built-in converter for greater convenience. You can use car battery or household outlet as power supply. The machine is also equipped with a built-in oil-water separator .Suggest to buy GX professional external filter if you need enhanced filtration performance..
- Please read user manual carefully before turning on compressor. Quick connector : M10*1, 8MM female connector. Product size: 11.8*6.1*12.4 inch , weight: 29lb. ATTENTION: when filling is complete, please close the bottle valve first (when filling bottle) and then open compressor's bleed valve to release line pressure . All pressure must be released from compressor before starting. First confirm the maximum safe pressure of your gas cylinder, do not over-inflate, otherwise it will cause safety problems.
- Note: when add coolant first time, add full tank, turn on switch (don't press start button), water pump will run, coolant will flow into inner water pipes, then keep adding more coolant until water tank is full. Package includes: CS4-I pcp compressor, filling hose, 12V dc cable, ac cable, user manual, accessory bag.
- Helpful Reminder: All machines undergo water testing before leaving the factory, so it is normal to find residual water in the tank upon receipt. Additionally, the timer readings are random numbers and do not start at zero.
Description
Compared to the small, boxy compressors on the market, GX features a patented structural design for the CS2, CS3, CS4, and 5K models, with different compression mechanisms. Years of continuous improvement, such as the addition of roller bearings at the top of the connecting rod, allow for better movement and less wear on the rod and wrist pin, significantly extending service life and enhancing performance under high pressure. NOTICE:This CS4 compressor supports the max design pressure 5800psi, but the burst disc coming with compressor only bear about 5000psi considering safety pressure. If fill over 5000psi, it will be blown up. If you really need the higher pressure, put 1 more burst disc into the valve.
Brand: GX pump
Voltage: 12 volts
Recommended Uses For Product: pcp compressor filling
Power Source: Corded Electric
Noise Level: 70 db
Voltage: 12 volts
Recommended Uses For Product: pcp compressor filling
Power Source: Corded Electric
Noise: 70 db
Additional Features: AC & DC Adaptable, Automatic Shut-Off, Oil-Free Pump, Quick Inflation, Silent Operation
Maximum Power: 350 watts
Capacity: 6.8 liters
Maximum Current: 29.17 A
Air Flow Capacity: 11 liters per minute
Maximum Horsepower: 350 watts
Hose Length: 19.6 inches
Tank Volume: 6.8 liters
Maximum Pressure: 400 bar
Item Weight: 33.7 pounds
Material Type: Metal
Item Highlight: Super Quiet & Fast Fill ,Portable,Auto Stop ,Built-in Home 12V Converter, Water and Fans Cooling, 5 Hours Continous Work
Brand Name: GX pump
Included Components: compressor, hose, 12v dc cable, 110v ac cable, user manual, accessory bag
Model Number: GX-E-CS4-I
Model Name: CS4-I Portable PCP Air Compressor
Number of Items: 1
Manufacturer: GX
UPC: 755642825145
Unit Count: 529.11 Ounce
Item Type Name: pcp air compressor
Manufacturer Part Number: GX-E-CS4-I
Color: Red+black
Style: Portable
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Wednesday, Oct 21
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
I have a Nomad II that broke down after two years. I had to repair it a few times since, so I wanted to get a new PCP air compressor and keep the Nomad II for backup. After doing my research, I decided on the GX CS4i. This compressor cost less than the Nomad, but in my opinion is way better. Faster fills, water cooled, longer run times, quiet, and a higher PSI fill rating. I did have one minor issue at just under a year of ownership, the water pump went bad. I check to see if it was getting voltage to the water pump, which it was so I contacted GX Pump customer service. I received a new water pump shipped from China two weeks later. That fixed the issue. It's not their fault that a vendor's supplied water pump went bad. Taking care of the customer, that's what counts. I don't think you will find a better PCP air compressor then this one for under a $1000. Also, their new GX Pump PCP compressor oil/water separator filter is another great product.
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Reviewed in the United States on June 8, 2025 by Mike G.
I am using this compressor to fill the small PCP tanks on my 10 meter air pistol. I eventually will also use it to fill a small air tank, as well, but right now I don't have a separate tank, just the two cylinders for my pistol. I did also buy the GX filter as an additional preventative measure against moisture getting into the cylinders. The compressor was easy to fill with distilled water for cooling. I keep mine inside so there is no risk of freezing. I did have to move the compressor around, bumping it slightly as the instructions recommend to get the water to flow properly through all the tubes. I definitely recommend taking the cover off when you are filling so you can actually see the water fill the tubes to make sure there are no air pockets. This was very easy to do. Once the water was filled and the filter hooked up it was ready to go. I've used it to fill the cylinders a few times and it does so up to the 200 BAR max of these cylinders in just a couple of minutes. This time includes filling the filterup to pressure as well. It is pretty darn fast in my opinion. The auto shut-off worked exactly like it was supposed to, shutting off at my set pressure of 200 BAR every time. I am using it with house current but it also comes with a power cable to connect directly to a battery, so this is a nice feature if you want to take it on the road with you. It is not that heavy and the handles on the top make it easy to carry. SO far, I am very impressed with this compressor. I don't think you can go wrong with this purchase.
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Reviewed in the United States on March 4, 2026 by David J.
My experience with the GX-E-CS4-I Air Compressor is noted by these items: This unit was purchased and this review is based on my perceived value and the function of the unit. Features of this unit that influenced my purchase was quality construction, ability to fill 1.5-2 L bottles, availability of repair parts and ease of set-up. - Shipment was quick and well packaged. The compressor was in great shape when delivered to my door. - Very easy to set up with the written instructions. Just follow the steps and you're up and running in under 30 minutes. - The only assembly to this compressor was adding a coolant to the tank (I used anti-freeze) and connecting the hose. - I added the GX Pro Grade Filter while setting up the compressor for quality air delivery. This is something you should NOT skip if you are putting air into expensive PCP equipment. -Once I set the cut-off pressure and back-up pressure limit, everything performed without a hitch. I have now officially retired my hand pump and can fill my equipment and bottle without breaking a sweat. I'll update this review after using the compressor through the Summer. UPDATE 7/9/26: After running this compressor for over 3 hours total, I have a couple of numbers to run. Just filled up a 98ci (1.6l ) bottle to 300 bar and it took 42 minutes. For an FX DRS 700mm pcp it filled up to 230 bar in 9 minutes. No issues with the pump, filter or bottle.
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Reviewed in the United States on July 7, 2026 by HDSportsPhotography
Excellent compressor! Has all the bells n whistles. Fast fill time. 68ci tank fill from 0-4500psi in 25 minutes. Have filled many tanks with great times. Can fill for 5 continuous hrs with no down time for large tanks. Big perk is it's extremely quiet! In addition has a grease pot which allows you to turn knob every 4-6 hours to lubricate the pump. Awesome feature! Have owned quite a few cheaper compressors n by far this one is superior. Costly but you get what you pay for. If your on the fence about buying this compressor it's definitely worth the cost. I couldn't be happier! Has good instructions with an itemized parts list which is great for if n when could need repairs. Don't anticipate that for a long time. Very pleased with this purchase! GREAT COMPRESSOR! Also has auto stop setting ability with a back up setting to your setting. Pump does not get anywhere near overheating due to the onboard water tank for great cooling of pump.
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Reviewed in the United States on September 7, 2025 by C M
This is my first compressor. It was on the costly side of what I wanted to spend but after reading the reviews, I was 80% sure this was the one. We needed the ability to refill 2L scuba tanks in a hurry and this machine is a workhorse. While the others below $1,000 were fan cooled, this one is water cooled. Water cools it down like a radiator in your car. This machine can run for 5 hours without the need to cool down where the others were 25 minutes on, 25 minutes fan cooled. We easily refill 2L scuba tanks in half an hour. We bought a vibration time meter that is sticks to the compressor as it requires a full turn of the Grease Knob every 5 hrs. I’m told it’s like changing the oil in your car and very much required. I did make the mistake the first time of not closing the Bleed Valve and wondered why the tank wasn’t filling - rookie error, and probably the one the reviewer with one star made as well. The 12v inverted is built in so this unit is very compact, heavy but very compact. The instructions are straight out of China with poor grammar but still understandable. Haven’t had to communicate yet with the manufacturer so can’t speak to that. To refill scuba tanks traditionally, one must drive their tanks to a dive shop. It’s not on demand so you have to drive to the dive shop the next day too. Very inconvenient. With this compressor, we can literally be ready to jump back in the water in less than an hour! We can also fill tanks utilizing the 12v cable hooked up to our car in any isolated dive spot accessible here in Hawaii. A true game changer for what we need it to do! Go get yourself one and life will be easier and more fun!
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Reviewed in the United States on April 7, 2024 by 100,000 gal saltwater pool guy
Item appears to be used. The information about this item on Amazon clearly states that "Note: before first use, it must be filled with 500ml of neutral distilled water or antifreeze", but this unit was full after only 150ml, so I took off the cover to see why (see pictures 1 & 3). It simply had been filled before and not completely drain. The fill cap for the coolant tank was extremely tight and the tank had visible rust inside at the bottom. Now, the compressor appears to be well made, and the accessories appear new, but the unit clearly appears to have been used. Two of the screws on the cover appear to have been stripped (hard to believe the factory did this but possible), but the converter (as seen in pictures 2 & 4) clearly has been fingerprints all over it. Once again hard to believe that this was done in a clean manufacturing environment, but possible. I returned this unit and order hopefully a "new" one. I received the second "new" compressor, and it was full after 250ml of antifreeze?!@ Now, it is possible that the distributor is filling each compressor and quality checking each prior to shipping to Amazon, but that is hard to believe because they left the cooling system three fourths to half full on these two compressors respectively. Now, I am going "try" this allegedly new unit and if it performs well keep it, but I have not been able to find the warranty on this compressor? At this price point and no warranty information? That is cause for concern, but once again your mileage may vary. UPDATE: After studying the CX CS4-I cooling system, I believe if the compressor is run on it's right side (the unit has feet on the right side) that the cooling cavitation issue would be solved or prevented (the inlet would be at the top and the outlet at the bottom of the radiator). This would allow heated inlet at the top and cooled outlet at the bottom of the radiator respectively, and cooled inlet on cylinder head lower than the heated outlet which would be higher (best for efficiency). My only concern would be the built-in oil-water separator being gravity assisted due to it's placement in the case that may need to be vertical in it's orientation. If this was an automotive cooling system then the upright running of the compressor would cause cavitation issues because both inlet and outlet are at the bottom of the radiator (and the inlet on the head would be at the same height as the outlet which is not ideal), part of which could solve by rotating the radiator 90 degrees counter-clockwise if you decide to run compressor in the upright position (vertical) but would not address the inlet and outlet on the head being the same height. Pictures 6 & 7: The blue arrows indicate cooled water and the red arrows indicate heated water . . .. the solution . . . lay the machine on it's right side (which has feet, so someone was planning on it) and the cooling system has no cavitation and is in it's most efficient configuration. Picture 8: Red arrow - cooling tank, orange arrow - compression cylinder, green arrow - gear box, blue arrow - electric motor, yellow arrow - cooling tank. Solution, lay the box on it's right side and cavitation (air pockets) is prevented, and system is at peak efficiency for cooling. SECOND UPDATE: It is not recommended to run the compressor for any long period of time on it's right side because the unit uses a gravity-assisted oil-water separator (which is quite common in many compressors in this category). The purpose of this separator is to remove both oil and water from the compressed air to ensure that the air reaching your air gun or tank is clean and dry, preventing damage or degradation. This unit has an orientation limitation due to separator's gravity dependency because a vertical oil-water separator relies on gravity to help the oil and water separate and settle. In a horizontal orientation, gravity would not work in the same way on the air stream. The oil and water droplets would be suspended in the airflow, and they wouldn't have a clear direction to settle. This would likely result in poor separation and could cause both oil and water to remain in the air stream. I believe that if you run the unit for 10 minutes on it's right side (horizontal position) that would purge the unit and prevent cavitation but then run the unit in the vertical position, so the separator works properly. THIRD UPDATE: But after more research I believe I found the best solution and that is to turn the radiator 90 degrees counter-clockwise, and I can say it will work with the GX CS4-I, it is a close fit on the right side (viewed from the front) because of the built-in 110v to 12V DC converter has limited clearance. The left side with the radiator inlet and outlet cleared without incident. When I refilled the coolant, the radiator slowly purged itself with the compressor off. I then ran the unit, and the pump head purge itself and I was able to add more coolant than I took out (about 25 mils plus or minus). I was using automotive cooling systems as a guide, but if you look closely, you will see that I hookup the warm inlet at the bottom and the cool outlet at the top of the radiator, because of cavitation (air pockets). The opposite of normal automotive cooling . . . because of the water pump in this compressor not producing enough pressure, it is not like automotive pumps working in a closed high-pressure system. This compressor uses an open non pressurized system with low pressure aquarium pump . . . therefore, fluid dynamics would be controlling, and air bubbles (pockets) rise in coolant and the outlet being higher than the inlet would be self-purging (and not rely on higher pressure from pump to purge the cavitation), which it now is. NOTE: The pictures are not in proper numerical order due to updates (my pictures order was changed). Fourth Update: I have two separate shooting locations, so I own two FX Impact M4 Snipers and have mirrored the setups at both. I recently purchased another GX-E-CS4-I compressor and had to return it immediately. It was leaking air straight out of the box, and several accessories were missing (the box appears to have been previously opened). I’ve now had bad luck with multiple units from this brand. In theory, these compressors should be perfectly adequate for my needs since I only fill one airgun at a time. I’m going to step up to the higher-end models and see if I have better results. Once, GX improves their quality control, these should be excellent compressors at this price point. Unfortunately, that hasn’t been my experience so far. Your mileage may vary. Fifth Update: Okay for Father's Day I was given a newer version of this machine . . .. I have to say they fixed the radiator issue (rotated it 90 degrees) and added a hour counter 000001.00 (down to 1/100 of hour). This now represents the most compressor at this price point. The last three pictures are the new updated machine. They update the coolant lines, the fittings from the cylinder head, and maybe more. The fit and finish is better than the last three machines. It you need one . . . this is the best I found at this price point. Time will tell about the longevity.
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Reviewed in the United States on January 2, 2025 by pc.upgrades
Excellent compressor. Very quiet. I've had no issues
Reviewed in the United States on August 8, 2026 by Kris
I have a pcp air rifle with a .48l tank and after attempts to fill with other less expensive makers with the same claims I was able to fill this tank in 3 minutes 59.27 seconds! This was using 110v. Very simple to use manual gages that were accurate. Very satisfied with purchace.
Reviewed in the United States on September 4, 2026 by R. Teves