PetSafe Electronic SmartDoor is the perfect addition to the smart house. Unique and innovative, the Electronic SmartDoor is operated by the lightweight SmartKey worn as an everyday tag on your pet's collar. The SmartKey communicates with the SmartDoor through a radio frequency and unlocks the door as the pet approaches and relocks automatically as the pet enters or exits. The SmartKey works like a garage door opener, so as long as your pet is in the range you've selected, the door will unlock. Designed for the pet's safety and convenience, the door has three levels of security; automatic, always unlocked, always locked and is battery powered, freeing the home of unwanted, hazardous cords. There are 250 different door codes, ensuring your door's individuality from neighboring doors. Our SmartDoor features a plexiglass flap with locks in both directions and an energy efficient, weather-resistant seal and insulated flap. System includes one SmartKey and can identify up to 5 SmartKeys, sold separately. Requires 4 D Cell batteries, not included.