K & H Thermo-Pond 3.0World's most efficient patented and successful low power pond de icer Low power consumption of 100 watts Keeps a hole in the ice of backyard ponds for only pennies per day Floats on water surface Never becomes hot thanks to its thermostatic control Safely use with a plastic pond or a pond liner Friendly to fish prevents the buildup of toxic gases under the ice Cold weather tested at 30F temperatures in northern Wisconsin MET Listed Warranty: 1 year