Approved Vendor 60022 Thermal Expansion Tank, 2 gal Tank Capacity, Stainless Steel, 210°F Max. Op Temp RS3542 AIR Rating 10kA at 120V AIR Rating 10kA at 120V AC Trip Curve A Curve For Use With QO and NQOD Panelboards Terminal Connection Lug Standards UL Listed ISO 6789 Number of Geared Teeth 30 Teeth 30 Calibration Certificate Included Yes Tether Capable Tether Capable Min Sub brand Water Heater Expansion Tank Market Residential Product Type Thermal Expansion Tank Expansion Tank Type Diaphragm Tank Capacity 2 gal Tank Material Stainless Steel Connection Material Stainless Steel Diaphragm Material Butyl Rubber Outside Diameter 8 in Overall Height 15 in Connection Size 3 4 in Thread Type MIP Precharge Pressure 40 psi Max These tanks absorb excess pressure caused by thermal expansion in closed plumbing systems