The PetSafe Microchip Cat Flap only opens when a pet with a programmed microchip walks up to the door. Programming a microchip to the door is quick and easy. You can program up to 40 pets making it great for multi-cat families. Customise your cat's access with the 4-way lock on the cat door. Set the door to locked, unlocked, in-only or out-only to keep your favourite feline safe and secure. Kit Includes PetSafe Microchip Cat Flap Screws Screw plugs Cutting template Quick start guide Key Features: Only opens for programmed pets, keeping unwanted animals out Suitable for up to 40 micro-chipped cats Reinforced, dual auto-latch with 4-way manual lock Low battery indicator Requires 4 x AA Alkaline batteries Quick Start Guide and Cutting Template Fits wooden doors, walls (using optional tunnel extension), glass windows and glass doors. Overall size: 239mm (h) x 220mm (w) Flap size: 135mm (h) x 145mm (w) PetSafe Cat Flap Adaptor (PSA-S) required when installing into metal, double glazing, and brick, sold separately PetSafe Cat Flap Tunnel (PST-S) needed for wall installation, sold separately Suitable Glass Cutout Size: 212 - 260 mm° Glass adapter not required for single glazing unless to cover an existing hole. Glass adapter is required for double glazing.