Eastman 60023 Thermal Expansion Tank, 4.5 Gal, 3/4 in Mpt, Steel, White Product Description The Eastman 4.5-Gallon Thermal Expansion Tank has a secure connection to water heaters that prevents dangerous build-ups of pressure. This water heater expansion tank stops hot water from backflowing into the cold water line and it also prevents hot water from escaping through the pressure relief valve and onto the floor. Constant fluctuations in water pressure can be dangerous and they can damage the water heater, properly installing a thermal expansion tank can solve all these issues. This product comes with a 6-year warranty and is factory pre-charged at 40 psi. Complies with NSF-61 and Lead Free law. UPC approved. From the Manufacturer This Thermal Expansion Tank prevents hot water from back flowing into the cold water line. This tank also prevents hot water from escaping through the pressure relief valve and onto the floor. The thermal expansion tank prevents constant fluctuations in water pressure that damage the heater. Features CAPACITY: 4. 5 gallons of water with a factory pre-charged pressure at 40 psi DIMENSIONS: 16-inch x 11. 1-Inch x 10. 9-Inch with 3/4-inch mip connection MATERIAL: It has a high-quality butyl rubber diaphragm and grade 304 stainless steel fittings for long-lasting performance DESIGN: The tank is designed to prevent hot water from back flowing into the cold water line, or escaping through the pressure relief valve OPTIONS: This thermal water expansion tank is available in varying capacity of 2 gallons and 4. 5 gallons of water; choose as per requirement USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.