Amtrol ST-5 Expansion Tank

Designed for use in closed, potable hot water systems, Therm-X-Span accepts expanded water as system temperature rises. This hot water is returned to the system when demand occurs. A thermal expansion tank, like Therm-X-Span, is essential in a closed system to protect your water heater. Application: Plumbing Tank Volume: 2 Gallons Max Accept.