DescriptionSolimeta Thermal Expansion Tank for Water Heater, Potable Water Expansion Tank, 4.5 Gallon, White. Expansion Tank Benefits: Preventing Pressure Buildup, Enhancing System Lifespan, Ensuring Energy Efficiency, Reducing Water Hammer, Protecting Against Leaks. The expansion tank serve plumbing systems where water is heated, including residential and commercial boilers, water heaters, hydronic heating etc. 4.5 Gallon value, 3/4" MNPT thread, with rubber thread protector. Precharge: 40PSIG MAX Pressure: 150 PSIG MAX Temp: 200°F. With high quality butyl rubber diaphragm and 304 stainless steel fittings prolong its lifespan.