WATTS WATER TECHNOLOGIES GIDDS-1030402 Watts Potable Water Expansion Tank, Model Plt-12, Stainless Steel Nipple, 4.5 Gallon, Lead Free - 1030402 From the Manufacturer Series PLT Potable Water Expansion Tanks are designed to absorb the increased volume of water created by thermal expansion and to maintain balanced pressure throughout the potable water supply system. Series PLT tanks feature a pre-pressurized steel tank with an expansion membrane that prevents contact of the water with the air in the tank. This prevents loss of air to the water and ensures long and trouble-free life for the system. These tanks may be used with all types of Direct Fired Hot Water Heaters (gas, oil or electric) and hot water storage tanks. IAPMO listed and ANSI/NSF 61 certified. Maximum Pressure: 150psi (10 bar)