Thermostatic Radiator Head: The ; 3-piece professional thermostatic radiator head suitable for valves with M 30 x 1.5 threaded connections and valves with M 30 x 1.5 threaded connections for radiator manufacturers. With high-quality materials: the ; TRV thermostatic radiator head is made of brass, steel plastic, not easily deformed or damaged. Easy to use and with a long service life. No specific temperature setting：The TRV radiator thermostat has no fixed setting range, affected by the heating temperature and room temperature can detect changes in outdoor temperature. Perfect for your home: The ; TRV thermostatic radiator valve heating system with frost protection and adjustment function that can provide adjustment assistance. And the upper limit of the zero adjustment ratio is 0.1-5. With 5 modulation levels:The TRV thermostatic radiator with 5 modulation levels and easy to install, if you need to turn off the thermostat, just use the modulation index arrow 0.