Selective entry – any animal can exit. The microchip reader is located on the outside of the cat door only Up to 12 months battery life (4xAA batteries – not included) Works with all common identification microchips and SureFlap RFID collar tags (not included). View our microchip compatibility checker below for peace of mind Stores up to 32 pet identities in memory. Remembers all registered cats even when the batteries are removed Manual lock stops your cat leaving or entering the house. Set to in-only to enable your cat to come indoors without being able to get out again Low battery indicator light flashes red when the batteries start running low giving you plenty of time to change them