Amtrol Therm-X-Trol Water Heater Expansion Tank for Tankless Water Heaters. Eliminates The Waste Of Energy And Water, Thus Saving Money. Protects the water heater and plumbing fixtures from premature failure. Prevents a dangerous pressure build-up in the system. Prevents the relief valve from going off. System connection: 1/2 in. NPTM. For use with tankless water heaters and point of use water heaters up to 2 Gal. Therm-X-Trol brand is the #1 choice of professional installers. Mfg #ST-1

• Eliminates The Waste Of Energy And Water, Thus Saving Money
• Protects the water heater and plumbing fixtures from premature failure
• Prevents a dangerous pressure build-up in the system
• Prevents the relief valve from going off