https://zenwriting.net/nervebo....mb0/choosing-cat-fla
You and your cat will both benefit from adding an animal flap into your bifold door. It can also keep extreme hot or cold weather from entering your home. First, you must measure your pet in order to determine the right size door flap is required. This will help you design a cat flap hole that is of the right size. Outdoor Access Even those with basic DIY skills can install a cat flap to an external back door. This can save you the expense and hassle of calling in an expert joiner, carpenter or handyman to complete the work