The HydroGEN PRO is the world’s first and only water cooled CO2 generator. Water cooling can remove 86% of the heat produced by burning propane and has many features not available in any other CO2 generator on the market. Compact for easy placement. This optional valve (used in place of a pump) is designed to be installed in a pressurized water line and to be controlled by your CO2 monitor. This is a high quality solid brass valve designed for years of service. You will need either a pump or a valve but not both.