The Cat Mate Elite Microchip Cat Door uses the latest in R.F.I.D.technology and offers major advancements in pet access control.To enter the house, the animal must have a Microchip ID from a Veterinarian implanted in the cat's neck, or a unique Cat Mate electronic Collar I.D.Disc (ref.310, not included).However, any animal can exit through the door, provided the 4 way electronic lock is not set to 'In Only' or 'Locked'.The door can be programmed for up to 9 cats, keeping all strays out.The LCD display shows selected entry and exit lock status, cat location and time since the flap was last used - for up to 3 cats.The cat door also features a timer function (e.g.to keep cats in at night), which works with the 4 way electronic locking system.Uses 4 AA batteries (6 to 9 months') not included.Self-lining to 4" (100mm) - suitable for single/double glazing, doors and panels, excluding metal-skinned panels.Wall Liner available for wall installation (ref.308 not included).If individual pet entry or exit control is required, this can be achieved with the Cat Mate Elite I.D.Disc control door (ref.Cat Mate 305).