SmartDoor Connected Pet Door Keys secure to your dog or cats collar and ensure your pets are the only ones walking through your SmartDoor. Keep critters and pests outside while giving your pet the freedom to come and go as they please. Each pet in your household will need their own key, giving you the ability to customize each pets experience and permissions with the SmartDoor. Decide when each pet has access through the door by customizing schedules if you need to stagger bathroom breaks. These pet door keys are compatible with the app-enabled SmartDoor Connected Pet Door and the Microchip Cat Door. For the best experience, make sure the key lays flat on your pets chest so it can be parallel to the pet door flap. Your pet deserves the best. Trust PetSafe to keep your pet healthy, safe and happy.