The K&H Thermo-Kitty Bed has a dual thermostat 4 watt heating unit buried deep within its thick, super soft, orthopedic foam base. It warms the surface 10-15 degrees above ambient air temperature to your cat's normal body temperature when in use. The washable cover comes in two colors and is attractive in any room in the house. Indoor use only. One year limited warranty. Â New fun and exciting fish print fabric Â Recommended for indoor use Â Uses only 4 watts Â MET Listed Â 1 year warranty small is 16" large is 20"