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 ; Nickel-plated bronze casted body with working parts in cartridge insert° For ease of service ; Controls include sensor, setpoint dial and valve actuator; components may be integral or connected by capillary tubes ; Meet ASHRAE Standard 102-1989 ; Temperature Range 48° F to 79° F ; High Capacity Thermostatic Radiator Actuator with remote sensor and 1-19/32'' collar diameter.