The SureFlap Microchip Pet Door identifies your pet by using its existing unique identification microchip or RFID collar tag (one tag supplied with the product), unlocking only for your pet and leaving intruder animals at the door. The SureFlap pet door is suitable for multi-pet households as it can store up to 32 pets in its memory. The SureFlap Microchip Pet Door is designed for large cats and small dogs. To fit through the pet door, your pet's shoulders should ideally be no wider than 6 and a half inches and the circumference of their waistline at its widest point should be no more than 20 and a quarter inches. The dimensions of the flap (the smallest area your pet will need to pass through) is 7″ (w) x 6.69″ (h). The size of the hole required to install the pet door is 8.15″ (w) x 9.21″ (h). The SureFlap Microchip Pet Door is programmed at the touch of a button and it can be installed in doors, windows and walls. A SureFlap Pet Door Mounting Adaptor is required for glass installations and one or more SureFlap Pet Door Tunnel Extenders may be required for wall installations. For metal skin doors, security doors, metal garage doors, and UPVC coated metal doors the mounting adaptor might be required if the pet door is not functioning properly with the initial installation. The SureFlap Microchip Pet Door is battery powered using 4 C cell batteries which last up to a year with normal use. Batteries are not included with the product. When the batteries start to run low, an indicator light will flash. The SureFlap Microchip Pet Door has been tested on raccoons in a zoo environment. During these tests, the raccoons were not able to gain access.