The K&H Thermo-Kitty Bed includes a dual thermostat, 4 watt heating unit buried within its thick premium polyfil pillow base. It warms the surface 10-15 degrees above ambient air temperature when not in use. When your pet lies in the bed it warms to your pet's normal body temperature to keep them cozy warm. The heater is removable and the cover is machine washable. Indoor use only, MET Listed, one year warranty.