The KSD 301 series thermostat is a fully closed temperature relay with a shell sensing the temperature by contact with the double sheet metals.It enables two contacts to move quickly for the purpose of switching on or off the circuit through the principle that the disc sheet metal deforms under action of temperature and jumps instantaneously at such point of temperature in combination with the mechanical action.This KSD301 thermostat is used either as temperature control and safety limit for household electric appliances and widely applicable for coffee maker, water heater, immersion heaters, electric cookers, microwave ovens, automatic toasters, etc.