The sensors are special used for overheat alarm and protection. PTC Thermistor/temperature-controlled sensors are made of mini heat-variable resistors. The controlled temperatures range from TK30 degree to TK180 degree There is a 5 degree interval between the controlled-temperature TK according to the specification. One and six cores sensors are available, according to customers' ' requirements. Advantage: Small size, endurance strength, good stability and excellent sensitiveness. They are all DIN 44080, DIN 44081 standard.