Danfoss RAS-CK 5025 — self-acting thermostatic radiator sensor (control head), OEM order code 013G5025. The RAS-CK 5025 is a self-acting thermostatic operator (control head) for Danfoss radiator valve bodies. It modulates the valve in proportion to room air temperature to hold the set room temperature without any external power or wiring; the liquid charge gives stable, hysteresis-controlled operation and the sensing element is built into the setpoint dial, sensing the air immediately around the valve. Setpoint range 8 °C - 28 °C. Features: frost-protection setting, setpoint limiting and locking. Valve connection M30x1.5. Colour Black RAL 9005 / White RAL 9016. Housing plastic. Genuine Danfoss part; specification quoted verbatim from store.danfoss.com (code 013G5025). OEM P/N 013G5025, EAN 5702420054803. HS 9032.10.