The SureFlap Microchip Cat Flap has been designed to keep intruder animalsout of your house, making sure your pets feel safe and happy in their ownhome. The cat flap is able to recognise either the microchip alreadyimplanted in your cat or the Sure Petcare RFID Collar Tag (sold separately)and will allow entry to your house for your authorised cat(s). The cat flapis selective entry only and allows any animal to exit. You can program andstore up to 32 pet identities in the cat flap's memory and it is easy toprogram at the touch of a button. Product specifications: FlapOpening 142mm (W) x 120mm (H) Hole Dimensions 165mm (W) x 171mm(H) Exterior Frame Dimensions 210mm (W) x 210mm (H) TunnelDepth 70mm Batteries 4x AA