The Thermo Cube is a unique patented electrical device that plugs into a standard 15 amp electrical outlet and turns power on automatically according to outside air temperature saving money by using power only when temperatures require heating or cooling. There are five models available with different temperature ranges to choose from. Cold weather model TC-3 turns on at 35?F off at 45?F and is ideal for home and farm applications such as pond de-icers unheated rooms pump houses greenhouses boats and RV s.