Continually monitors and adjusts room temperature For consistent comfort and relief from under-heating and overheating ; Designed with the higher capacity normally required by USA heating systems ; Valve seat disc, which is made of resilient material (EPDM), ensures tight shutoff on steam or hot water systems ; Meet ASHRAE Standard 102-1989 ; Requires no electrical connections ; Nickel-plated bronze casted body with working parts in cartridge insert For ease of service ; Pressure Ratings (Hot Water (PSI)) 150 PSI maximum ; Straight Pattern in. Valve for High Capacity Radiator.