Internal thermostats automatically adjust the Pet Bed Warmer's temperature as needed to create a comfortable resting area for dogs and cats. They're pre-set to heat to your pet's natural 102°F body temperature when he/she lies on the pad. When plugged in but not in use, the Pet Bed Warmer will maintain a temperature 10-15°F greater than the ambient room temperature. The Pet Bed Warmer is the essence of simplicity and has no on/off switch to monitor. Plug it in and the product will begin to warm automatically. Its soothing, gentle heat will not exceed the natural body temperature of a dog or cat, allowing your pet to enjoy hours of warmth. It slides into any zippered dog or cat bed and is recommended for beds with at least ½ inch of padding between the warmer and bed surface. Simply plug it in and the warmer will generate a subtle, comfortable heat that any pet is sure to enjoy. Please Note: This is a Pet Bed Warmer, it should only be used inside of a pet's bed and should never come in direct contact with your pet. Every size Pet Bed Warmer uses less energy than most light bulbs, helping keep your electrical bills low. The K&H Lectro-Soft has been tested rigorously and certified by MET Labs. Their certification means this product adheres to strict electrical safety standards.