The HabiStat Temperature Thermostat (or "temp stat) is an on/ off thermostat that is ideal for controlling the temperature of heat mats and other heaters up to a maximum load of 600 watts. The thermostat switches a heater on full power until the set temperature is achieved and will switch the heater off until the temperature drops below the set value. With an accurate dial calibrated in both Fahrenheit and Celsius, the HabiStat Temperature Thermostat is easy to use. If you are unsure which thermostat is right for you, download our thermostat user guide. The HabiStat Temperature Thermostat has a five year guarantee. Please note this thermostat is not suitable for controlling light bulbs.The constant turning on and off of the light bulb would not only distress your animals, but would cause frequent failure of the lamps. This, in turn, is very likely to make your thermostat fail. For light emitting heat sources use HabiStat Dimming Thermostats.