The battery operated PetSafe Staywell Deluxe Infra-red Cat Flap helps keep out unwanted cats from your home. Your cat wears the infra-red collar key which, when in range of the cat flap, triggers it to unlock; and let them have safe entry into the home. Suitable for most materials. Tunnel extensions can be used to fit any depth of wall. Suitable for cats up to 7kg. Made from abs plastic. Suitable for small to medium sized cat . Operated by magnetic collar key with . In/out/opened/locked. Manual locking system. Max shoulder width 15cm. Can be fitted into windows. H17.5, W16.8, . Manufacturers 3 year limited hardware guarantee.