The GX CS4 Compressor Isn’t Replacing the CS3 Models – The CS4 Is For People Who Need to Fill 6.8L Tanks Or Need More Air In General

A fellow asked me that if the CS4 is an upgrade then why are both the CS3 models (the one with the external 12 volt power supply and the one with an internal integrated supply) still being sold on Amazon. I explained in my email back to him that the CS4 does have a longer run time and a faster fill rate but it’s not a replacement. I figured I better expand on the email because if one person is wondering then others are as well – the models are for people with different needs and budgets.

The CS3 series will work great for anyone filling either a small airtank like my 18 cu ft Omega, or an airgun directly. It’s light and portable so you can do that no problem. The limiting factor is that it is air cooled and has a 20 minute duty cycle after which it needs to cool down. I bought mine in November of 2020 and used it right up until I bought my CS4 in January 2023 and I am certain one reason it held up so well is that I would never run it for more than 20 minutes. If I was filling something that took more than that, I would run it for 20 minutes and then let it cool down. It could top off my Hatsan Gladius or FX Impact Compact Mk.II in far less time than that – it was filling/refilling the Omega bottle that took longer.

The CS4 notably has a water/fluid cooling, the ability to add grease every 4-6 hours of run time, a more powerful motor, a faster fill rate and the ability to compress air up to 400 bar (5,801 psi) and a detachable air line. Yes, it does reflect a lot of lessons learned by GX but it’s not a replacement of the CS3 – the CS3 is still there for folks who want a smaller and lighter unit that is more portable and aren’t filling bigger tanks.

I bought the CS4 because I am getting into some airguns that use a lot of air – a Gauntlet .30 and a Leshiy 2 in .22 so I bought a 6.8L Air Marksman carbon fiber tank. You may be wondering how is a .22 an air hog – well, it gets 28 semi-auto shots and then needs to be topped back off and it’s onboard reservoir is rated at 300 bar. I can fill it one time from the big bottle and then the bottle is close to 250 bar plus I plan on buying the bigger optional air cylinder for the Leshiy.

My point is that all of these were going to require the air pump routinely running longer than the recommended 20 minute duty cycle so I really needed to make the move.

In short, the CS3 is for folks who need a compressor to fill and airgun directly or small bottles plus save a little money. The CS4 does have newer technology and is for users who want to fill airguns directly plus have a long enough duty cycle to fill up to a 6.8 liter tank. I bet it could do bigger as long as you honored the remarkably long 5 hour duty cycle of the CS4 but I’ve not used it enough to say that. The CS4 is more expensive than the CS3.

Here are posts I have written about the CS3:

Here are posts I have written about the CS4:

Here are photos of the units side by side:


I had to buy these compressors with my own money and these posts were not paid for – I want to be clear about that. My experiences with both the CS3 and the CS4 have been very positive and I have no reservations recommending either to you.

Oh – also – a guy emailed me the other day asking me about the GX CS2 and I had to tell him that I do not have any experience with that model. Folks, I only have these two. Before the CS3 I had a Hill Mk. IV hand pump – the Hill was excellent but that’s the limit of my high pressure air compressor experience. I am a licensed SCUBA diver but always bought my air at a dive shop so I had a little knowledge from that plus many, many years of industrial and shop pneumatic work but that was only up to 175 PSI.

Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.