GX PUMP GX-E-CS4 Portable PCP Air Compressor, 350W Powerful Motor,Max 5800Psi/40Mpa, Water and Fan Cooling, 5 Hours Continous Work, 12V Auto Stop Paintball Air Compressor

I was looking for a better replacement for my Yong Heng compressor and purchased a GX water separator filter and noticed the filter to be well thought out and built like a tank. I was impressed so much with the filter build and performance I decided to purchase a GX GS4 compressor. Upon opening the packing crate I removed the compressor and read the instruction sheet. Imagine an instruction sheet with a compressor. (Some do-not. have one). I live in Utah wher winters get cold. My compressor would be in my shop so used a 70/30 mix of green antifreeze with distilled water and had a 7 ph factor. I bought the compressor to mainly fill my 6.7 L tank. I started the fill procedure as per directions such as opening the vent to let compressor start then closing vent to prevent the compressor from starting under pressure. 3.4 hours later my carbon fiber 6.7L tank was full at 4350 psi. I shut of compressor but let the coolant flow through the compressor to cool it down. Over the time filling the tank it never got really hot as the coolant radiator and fan worked great to keep it cool. It has a pressure shut off and a back up shut off for safety. The compressor is fairly quiet in its operation. The quality of the build is amazing. It is really built strong and for reliability. It does not struggle to fill the 6.7L tank. Most of the other tanks need a cool down period filling tanks that size. I am not only impressed with its capability, but also the machining, and quality of the unit. The unit will compress air to 5800 psi and has safety devices to keep excess pressures from causing issues. This is a PORTABLE unit and weighs 29 lbs and can run on 12 volts or 110v. It uses 345 watts with compressor on. I tried to save money on lesser quality compressors but they did not perform well or died within a few months. This GX compressor is not that more expensive. It truly is a well made compressor of quality workmanship and design with safety systems and pressure back up switch (2) to keep you safe. I appreciate the safety as well as the unit. NOTE: If you have any high pressure compressors look into the GX Drain Filter as it by far is the best strongest oil and water pcp filter out there. I am not affiliated with GX but after buying the compressor and filter I am and will be a GX customer. Dr.Dave. Utah

I'm absolutely thrilled with my new GX-E-CS4 pcp air compressor. As an avid air gunner, I was in the market for a reliable, high-performance pump that could handle my needs, and this one has exceeded my expectations. One of the standout features for me is the ability to pump up to 400 bar. I own a Huben GK1 air pistol that is rated for up to 350 bar, so having that extra headroom is fantastic. I can now fill my pistol to its max capacity without any issues. The compressor handles the task with ease, and I'm impressed by how quickly it can fill even my larger air cylinders. Another feature I really love is the water cooling system. I've had troubles in the past with other pumps overheating when filling larger volumes, but the GX-E-CS4 stays cool and composed even when I'm filling my 6 liter bottle. It's so convenient to be able to top up my air reserves without having to worry about the pump conking out. The price of this compressor is also amazing considering all the functionality and performance it offers. I was a bit hesitant at first, but after using it extensively, I can say with confidence that it's worth every penny. Finally, I have to mention the stellar customer service I received. I had a minor issue pop up, and the company was quick to diagnose the problem and send me a replacement part. Their responsiveness and willingness to stand behind their product is refreshing. Overall, I highly recommend the GX-E-CS4 to any PCP air gun enthusiast. It's a game-changer!

I really like this compressor. It a set the pressure stop, turn it on and forget about it. I was worried at first and didn't trust the automatic stop, but after a hundred or so fill ups, it works perfect. Its accurate too. I have it set at 3k psi and it matches the small handful of PCP airguns gauges. Fill time is plenty quick in my opinion and the decibel level is bearable enough to run inside the house. It's quieter than my shop compressor by a wide margin. I bought Amazons extended warranty which makes it the best insured value for a compact compressor on the market. If I was to have one complaint, its that the external power inverter doesn't have an on/off switch. I continuously have to plug and unplug it in for use. I'll be buying a switched power strip to solve the annoyance. But other than that, this compressor is great. I'm glad I invested in it for my hobby and would do it over again without hesitation. If you're on the fence abut such a large purchase, if you commit, you'll be happy you did. It's made filling my tanks and PCP's so easy.

Used this compressor a couple of times to fill my PCP and, wow. Great quality, worked right out of the box, no leaks, no problems. Haven’t used long term yet, but so far so good. Some stuff no one has mentioned/ details: 1) The instructions are pretty good, and state that the air coming out of it is dry and suitable for breathing purposes. I wouldn’t, but that is what it says. It gives detailed instructions for first time and then repeat startup procedures, and is written in readable English. It also has a full exploded parts diagram and parts list. 2) I went with a no-compromises set up, with an additional oil-water separator and an additional in-line drier and they *don’t seem to be necessary*. The compressor has a built in oil-water separator that works quite well! After filling, the bleed on my extra external oil-water separator was bone dry, and the bleed on the compressor itself spat out water as expected. I cautiously say you don’t really need an additional moisture solution if you live in dry or semi-dry climate. 3) The air hose it comes with are standard air rifle Foster type quick-connects on both ends 4) It wasn’t clear but the water cooling is actually a small very good functioning radiator and water pump. I was worried it might have just been a water jacket for the thermal mass, but that is not the case. The instructions say over and over to fill the water first before turning it on. Mine actually came with the water reservoir about half full of water already, so even if you were dumb and didn’t fill it, it probably wouldn’t have ruined the water pump outright. 5) The AC-DC converter appears to be of good quality and works well so far. 6) Comes with a quick-connect plug for the air line, and instructions that with the plug in place you should get 250 bar in 38 seconds or so. I confirmed this. 7) Took about 10 minutes to fill my ~600 mL bottle from 100 to 250 bar, including the extra volume of the external oil-water separator and big drier. It would probably be a lot faster without the extra volume, as stated above in point #2. Since I have them, though, I will continue to use them. 8) The automatic shut off with double-redundancy is, in my opinion, a critical safety feature. I couldn’t imagine filling a potentially dangerous high-pressure air device without one. 9) Manual states it can be used vertically or horizontally, in case that matters to you.

great machine and quiet

I've had this pump for almost a year now, through a moderate air gun season. I own a Benjamin Bulldog M357, Hatsan Piledriver .457 and AEA Harpoon with barrels and round retainers in .457 and .495 ... I also have a 6.8L, 4500 PSI SCBA tank. I bottle feed the Bulldog, top the Piledriver every 4 shots, and run 6 single fire cartridges for the Harpoon. Approximate hours run is 40. Including hours-long sessions and on-off cycles. It has proven solid and durable under both long cycles and short fill cycles. My setup is mobile, that was one of the considerations for this compressor. I run a 2x30aH battery bank 'in the field' (at the range, or out in the desert,) and this little compressor will run on those batteries for 4-6 hours, topping up tank. The compressor is not 'light' by hiking standards, but it IS light enough to be semi-mobile. I pack my kit on a sport touring bike, and head into the desert like that. Portability is great! As far as its functionality, it checked all the boxes. I needed a pump that I could pack into TourMaster bag, with 2 batteries to run it. This compressor nailed every point I needed. In the field, at home, filling bottles, guns, or cartridges, it gets the job done. It's also a great conversation starter at the gun range. First the jokes, then I ring the 200 yard bell, then the serious discussion about air vs. powder, and the punchy little compressor that runs my show, begins.

I've been using the CS4 for two weeks now and really like it. The longer run time, faster fill rate, detachable air hose, liquid cooling and the ability to add grease every 4-6 hours are all cool features. I read their instructions, flushed the cooling system and then filled it with a 70/30 Zerex G48/distilled water antifreeze mix to limit corrosion and lubricate the pump. You can use distilled water if you so prefer. I tested the unit start with just the air hose, then the air hose and the filter. I pressurized a 6.8 liter tank to 257 bar in 3 hours and 22 minutes straight and the exhaust temperature never went over 101F. The reason for the odd pressure is that the compressor's limit switches / stop switches actually stop short of the pressure you set. That's no big deal because once I realized it, I adjusted the stop switch and topped it off the rest of the way to 300 bar. Since the initial fill I've topped that 6.8L tank again as well as my 1.5 liter carbon fiber tank. The CS4 is working great.

I bought the GX CS4 with the hope of filling my 6.8L tank. That did not happen. Compressor #1 (May): The START button would not stay engaged. Tech support had me disconnect the pressure gauge, and only then would the pump stay on. Of course, that meant there was no pressure reading or auto-cutoff. I sent photos of the pressure gauge needles to tech support at their request, and a new pressure gauge was sent from China -- only to be lost by FedEx after it hit the states. I returned the compressor for a refund and purchased a second, which arrived in two days. Compressor #2 (June): This one appeared OK initially, hitting 300 BAR in a dead-head test and shutting off automatically. However, it could not get past 100 BAR while attempting to fill my 6.8L tank. I aborted the attempt after 3 hours of run time and seeing no further progress. The following day, I did a quick dead-head test with target pressure of 300 BAR, and the pump starting slowing down noticeably as it approached 200 BAR. At 210 BAR, the pump stopped altogether – immediately followed by the power inverter erupting in a shower of sparks and smoke. Tech support suggested the piston head in the high pressure pump was “blocked” and offered to let me troubleshoot it. At this point, I had no confidence in the product and returned it for refund. The technical support is via e-mail. They seem eager to help, but there is an overreliance on extensive customer troubleshooting, and the back & forth response times are each one day minimum – presumably due to time zones. When the part they sent went missing, they expected me to call FedEx and find it.