All GX Pump PCP Compressors
GX Pump makes several portable electric compressors across two main families — the water-cooled CS series and the fan-cooled L series. My personal champion pick is the CS4-I, but here's the full lineup with notes on who each model is right for.
GX-E-CS4-I
Portable PCP Air Compressor — Water-Cooled with Integrated Separator
The water-cooled design, built-in moisture separator, and 5800 PSI ceiling make this the best-value serious compressor under $1,000. Covers the full range of PCP airguns on the market. This is the one I recommend without hesitation for most buyers.
GX-E-5K2
Dual-Piston 4-Stage PCP Compressor — Auto-Stop, 10hr Continuous Rating
The 5K2 sits above the CS4-I in the GX Pump lineup. Where the CS4-I uses a single-piston water-cooled design, the 5K2 runs dual pistons with 4-stage compression — a meaningfully more capable architecture. It combines both water and fan cooling and is rated for 10 hours of continuous operation, which is well beyond what most hobbyists will ever need. The built-in auto-stop feature shuts it down when it reaches your target pressure. It also includes an integrated moisture filter.
The tradeoff: it goes out of stock frequently and the price reflects the step up in capability. If it's in stock and you want the most capable portable 110V option GX Pump makes, this is it.
Water-Cooled CS4 Series
Only the CS4 and CS4-I use water-jacket cooling. This is what separates them from the rest of the GX Pump lineup and most of the budget competition. Water cooling enables longer duty cycles and more consistent performance. If you're filling regularly, this is where to look.
GX-E-CS4
Same water-cooled core as the CS4-I without the built-in moisture separator. Pair it with a quality external filter and it does the same job at a slightly lower cost.
Amazon SearchFan-Cooled CS & L Series
The CS2, CS3, CS3-I, L2, and L3 all use fan cooling — not water cooling. Fan-cooled units are lighter and less expensive, but require shorter duty cycles and more cool-down time between fills. Fine for occasional single-gun fills; less suited to regular or high-volume use.
GX-E-CS3-I
Fan-cooled unit with a built-in moisture separator. The "I" adds some protection over the base CS3, but it's still fan-cooled — watch your duty cycles.
Amazon SearchGX-E-CS3
Base fan-cooled model. Decent for light use with a good external filter. Step up to the CS4-I if you fill more than occasionally.
Amazon SearchGX-E-CS2
Smallest of the CS series. Fan-cooled with a compact footprint. Occasional use only — not the right tool if you're filling multiple guns or filling frequently.
Amazon SearchGX-E-L3
Larger of the L-series fan-cooled units. Light and portable. Give it rest time between fills — especially in warm weather.
Amazon SearchGX-E-L2
Entry-level GX Pump option. If budget is the primary constraint and you're filling one gun infrequently, it gets the job done. Step up to a water-cooled unit for regular use.
Amazon SearchThe 1,200-member GX PCP Air Compressor Owners Group (run by Jason Song) is a great resource for model-specific questions, service tips, and real-world feedback from owners of every model in the lineup.