It is close until the surface reaches 125 Celsius degree and then the switch open. Automatically resetWhen the surface cools off about 5 degrees, the switch automatically close.Opening-closing durability: 10000 times or more (under rated load).General-purpose low cost, compact, large capacity, minute current thermostat.Application: for Household electric appliances, PC, Microwave ovens, Irons, Refrigerators, Electronic oven, Heating unit, Coffeepot, Water heater, etc.