The working principle of this design of is: the liquid temperature sensing head is to feel the room air temperature , and thereby changing the heating water flow , so as to regulate and control room temperature :i.e., when the indoor temperature rises , the thermal expansion of the temperature sensing material shall compress to the stem to close down the up to ,and on the contrary ,the stem shall to open up the valve. In this way, comfortable temperature environment for people is achieved. Features - Color: Assorted Color. - Size: 13.00X7.30X3.00cm/5.11X2.87X1.18in - Material: Brass. - If there is other auxiliary heat source(such as sunshine or other heater etc) in the room, the shall close down a little to reduce the water flow into the radiator, and achieve the of energy-saving in the end. - The temperature sensing in the temperature control controls the size of the and automatically adjusts the flow rate to achieve a comfortable temperature range. - The temperature can be adjusted separately for any room. Keeps room temperature constant. - Adopts precision production to the stable characteristics and high reliability. - Professional and practical design with beautiful appearance, easy to carry and use. Package list: 1 x Radiator