The SureFlap Microchip Cat Flap identifies your cat by using its existing unique identification microchip, unlocking only for your cat and leaving the neighbour's cat at the door. There is no need for a collar and tag to operate the SureFlap, which can sometimes get lost or snagged. The SureFlap is a selective entry cat flap - it prevents unwanted cats and animals entering the home, but any cat can leave. The SureFlap has a 4-way manual lock that can be used to lock your cat inside for vet visits or to keep your cat in at night. The 4-way manual lock enables locking to any combination of in/out. The SureFlap is programmed at the touch of a button and its two part construction can be easily installed in doors, windows and walls. A SureFlap Mounting Adaptor is required for glass installations and one or more SureFlap Tunnel Extenders may be required for wall installations. The SureFlap is battery powered using 4 AA batteries which last up to a year with normal use. When the batteries start to run low, an indicator light will flash. SureFlap is suitable for multi-cat households as it can store up to 32 cats in its memory. SureFlap is compatible with 9, 10 and 15 digit microchips (except those staring with 000, 010 or 020). The SureFlap has a 4-way manual lock to enable locking to any combination of in/out and a central magnet on the door prevents it from flapping in the wind. Install a SureFlap Microchip Cat Flap for peace of mind, knowing that your cat can no longer be bullied in her own home by the neighbour's cat. Your home becomes a secure environment for your pet, leading to a more relaxed animal. The dimensions of the flap are 142mm (W) x 120mm (H). This is the smallest area your cat will have to pass through.