This ball-lock gas in fitting makes it easy to inject low pressure (1-2psi) CO2 into the 3-in-1 and 4-in-1 fermenters when transferring beer to bottles or kegs as the slight pressure allows the beer to be pushed out, even against gravity. It can also be used for force carbonating beer in the fermenter once fermentation is complete. The post is connected to a 1.5" tri-clamp compatible fitting. This fitting can be easily sanitized by placing in boiling water (the rubber gaskets will last longer if they are removed as they may break down in boiling water after some time). The optional gas connector can also be purchased with the fitting, and the tailpiece will work with our 1/4" braided silicone hose.