Reset Temperature Normally Closed: When the temperature falls to the reset temperature, the thermostat contact can be connected again. (If the reset temperature is not reached, the thermostat contact is also disconnected) Normally Open: When the temperature falls to the reset temperature, the thermostat contact can be disconnected again. (If the reset temperature is not reached, the thermostat contact is also connected) Please Note : During installation, the temperature switch should be completely close to the mounting surface of the tested appliance.Do not collapse or deform the plastic / metal shell during installation.For metal temperature controller, when using, do not remove the insulating sleeve to avoid electric leakage.Not suitable for working in water.Not suitable for air temperature sensing, only applies to contact sensing.