Water Worker 2 Gallon Water Heater Expansion Tank is a diaphragm-type pre-pressurized expansion tank specially designed for potable hot water systems. It effectively controls water pressure build-up and prevents relief valve spillage caused by thermal expansion when water is heated. Featuring a 3/4" male pipe thread connection, this tank requires no maintenance and is compliant with codes in many counties and states. It is designed to maintain maximum allowable working temperatures up to 200 degrees Fahrenheit and has a standard factory precharge of 40 PSIG, with the relief valve set at 150 PSIG. The tank is listed with IAPMO and SBCCI and is NSF listed for the liner only, ensuring quality and safety. This model is an essential component for maintaining optimal water pressure and protecting your hot water system. Model Number: 993-024