The Danfoss 015G4290 Thermostatic Sensor is a mechanical radiator thermostat designed for use with Danfoss RA radiator valves in hydronic heating systems. Its built-in gas sensor detects room temperature and automatically adjusts the valve to regulate hot-water flow through the radiator, maintaining the selected comfort level. Suitable for residential and commercial radiator heating a... https://www.partshnc.com/015g4290-danfoss-direct-mount-actuator-with-dial-sensor-replaces-013g8200-replaces-013g8250