https://www.openlearning.com/u..../stormrask-sm75ta/bl
https://squareblogs.net/carrot....bike4/cat-flap-fitti
You and your cat will both benefit from having the cat flap inside your bifold door. It can also prevent extreme heat or cold from entering your home. The first step is to measure your pet's size to determine the size of the door flap you'll require. This will allow you create an opening for the flap that is the correct size. Outdoor Access Even those with no DIY skills can install a cat flap on an outside back door. will save you the cost