This product can be used with the SureFlap Microchip Cat Door, the DualScan Microchip Cat Door or the Microchip Cat Door Connect. When mounting in glass, this accessory allows mounting in circular holes with a diameter of 212mm (min) to 260mm (max). The total diameter of the mounting adaptor is 285mm. Using the mounting adaptor for wall installations enables you to install the DualScan Microchip Cat Door more easily because you can use it to fix the cat door to the wall without the need for messy adhesives. The mounting adaptor is not required to install the Microchip Cat door or the Microchip Cat door Connect in a wall as these products contain wall mounting screw holes within the front frame. The Cat Door Mounting Adaptor includes two parts, one for the exterior and one for the interior of your home. Now comes in 100% recyclable packaging.