Smart cat flap with microchip, only lets your own cats into your home. By reading the cat's ID microchip, it ensures that unwanted cats don't get in.Register up to 40 chips that have permission to enter.Works for cats up to 8 kg. The door can be locked in four different positions.A battery light illuminates when it's time to change batteries.When installing in a new door with a metal plate, a mounting adapter is required to prevent interference with chip reading. Chip not included! If your cat does not have a chip, you must purchase it separately. PetSafe chip tray fits.Maximum door depth: 70 mm. For thicker doors/walls you will need to purchase a tunnel extender. The tunnel extender adds 50 mm and can be connected in series.Dimensions of the cat flap: 239x220 cm (WxH).Depth: 72 mm. Battery requirement: 4 x AA (not included).