The Cat Mate Elite uses the latest in R.F.I.D. technology and offers major advancements in pet access control. Entry through the door is operated by either the Microchip ID your Veterinarian implanted in the cats neck, or our unique electronic Collar I.D. Discs not included for up to 9 cats - keeps all other animals 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 flap also features entry and exit control, a timer function e.g. to keep cats in at night and a revolutionary, secure 4 way locking system. When set to the 4 way setting any animal can exit the door, but only animals with a Microchip or a Cat Mate RFID collar disc can enter the door. 4 AA Batteries 6 to 9 months not included. Self-lining to 2in 50mm - suitable for single/double glazing, doors and panels, including metal. Wall Liner available for wall installation not included.