AUTOMATIC WARMTH: The removable dog heating pad is thermostatically controlled to warm to your pet's normal body temperature only when in use by your pet; we set the safest temperature so you don't have to MACHINE WASHABLE DOG BED: This heated bed features a non-slip bottom and is easy to care for, simply remove the heating pad and toss the plush dog bed into the washing machine for easy cleaning BOLSTER DOG BED: Elevate your dogs comfort level with the soft and fluffy bolster that surrounds your cat or dog in premium heated softness; it's so warm and cozy that it is like wearing a dog sweater for your pet, but in a heated pet bed SAFETY CERTIFIED: This pet bed has been tested & certified by MET Labs and exceeds USA/CA UL electrical safety standards; we safety certify the entire product for maximum safety - For indoor household use with 110/120 volt electrical current only SIZING: The K&H Thermo-Pet Lounge Sleeper is available in 2 sizes: Small 4 watt bed measuring 20.5" x 19.5" x 6.5" is recommended for pets up to 20 pounds; or Medium 7 watt bed measuring 30.5" x 24.5" x 9" is recommended for pets up to 40 pounds HOW IT WORKS: This heated bed may not feel warm to the touch when your pet is not in the bed; it emits a small amount of heat when not in use (pets can sense it), but only warms to max temperature when your pet is using the bed - see “How to Test” image