The Sureflap Microchip Cat Flap identifies your cat using their unique identification microchip, unlocking only for your pet when they enter the home, preventing intruder cats from gaining access.Sureflap Microchip Cat Flap is suitable for cats and has a flap opening of 142mm (W) x 120mm (H) - This dimension is the smallest area of the cat flap that your cat will have to enter through.The cat flap works by reading your cat's existing identification microchip (no collar required), compatible with all international microchip formats, stores up to 32 microchip numbers, runs on 4 x AA batteries for over 12 months, two part construction for easier installation, fits into doors up to 6cm thick with no accessories.The microchip cat flap can also be installed in glass from 3mm to 6cm in thickness. A mounting adaptor is required for glass and wall installations (sold separately). For non-micro chipped pets you can use the SureFlap collar tag.Key Benefits Selective entry any animal can exit.