The Temperature Thermostat is an on/ off switching device, that can be used with a variety of heaters. It has an accurate dial calibrated in both Farenheit and Celcius. Ideal for controlling heat mats, and other low powered heaters up a maximum load of 300 watts. 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. The temperature themostat is one of the best selling thermostats in Europe.