https://informatic.wiki/wiki/Fitting_a_Cat_Flap
A door with a cat flap lets your pet leave the house and return inside without you having to open the door for them. These doors come in different sizes to fit dogs and cats. They also come with features that keep out draughts as well as unwanted creatures. It is recommended to introduce your pet to the door before installing it. It will be easier to familiarize them with the size, shape and motion. Easy to install Cat flaps can be installed in a variety of locations - you can have one in your garage door or laundry room to give your pets