GX Pump CS4

Overview

A big step up from the fan-cooled CS models. The CS4 is a real 4-stage compressor with a built-in water-cooling loop: a coolant tank and a grease reservoir sit on top. It's powered by a 350W motor and reaches 5800 PSI (40 MPa). GX rates it at 70 dB and up to 5 hours of continuous running. It has a dual-needle gauge, two-level auto-stop, an hour meter, and overcurrent protection. It runs on 12V DC, from a car battery or the included 110V-to-12V converter, and the built-in oil/water separator is permanent, not a cotton element. Before the first run, fill it with about 300 ml of neutral antifreeze (GX says not distilled water). Don't turn the grease knob until after 4 to 6 hours of use. GX says the CS4 is meant for small high-pressure tanks up to 6.8L, not large cylinders. For those, they point to the 5K series. It weighs 29 lb and uses an M10x1 / 8mm quick connector.