With a turn of the knob, you can adjust the temperature of most heating devices! Plug in up to two compatible heat sources with a combined wattage of up to 150 watts! Turn your heaters down or back up depending on the ambient room temperature. Great for use with Zoo Med's Repticare Rock Heaters, Ceramic Heat Emitters, Reptitherm Under Tank Heaters, and Repti Basking Spot Lamps (combined wattage not to exceed 150 watts).