https://articlescad.com/fittin....g-a-cat-flap-567270.
A cat flap is a tiny door that allows your pet to enter and leave the house as they like. It can be placed in windows, doors and even in walls. It is opened when your cat pushes the body part through it. Microchip cat flaps unlock the door by recognizing your cat's unique chip. Magnet and infrared flaps require that your cat wear a collar equipped with an infrared or magnetic device to activate them. What is a cat's flap? A cat flap is an opening inside a door or window which allows your pet to go in and out of the house. They are