SureFlap Microchip Pet Door Mounting ExtenderThe SureFlap Mounting Adaptor is useful when installing theSureFlap microchip pet door into glass, walls and certain door types.This accessory allows mounting in holes ranging from 294mmto 320mm (11½" to 12 5/8") diameter. The total diameter of themounting adapter is 380mm (15").Each mounting adaptor includes two parts, one for theinterior and one for the exterior of your home.GLASS INSTALLATIONSWhen mounting the SureFlap microchip pet door in a glasspane, your glazier will generally cut a circular hole, leaving open areasaround the corners of your pet door. The SureFlap mounting adaptor covers theseopen areas, preventing loss of heat from your home and providing a clean, neatfinish to your installation.