2 Gal Thermal Expansion Tank

2 Gallon, Thermal Expansion Water Heater Safety Tank, Steel Outer Shell, Polypropylene Lined Water Reservoir, Heavy Duty Butyl Diaphragm That Flexes, Leak Proof Precharged Air Chamber, Reduces Pressure Build Up & Harmful Pressure Spikes, In Closed Water Systems, Temporarily Absorbs Expanded Water Overflow.