https://selfless.wiki/wiki/Through_Wall_Cat_Flap
Cat flaps for the door made of composite are a popular choice among homeowners. They offer a secure entrance for your pet. It also reduces the risk that unwanted animals will gain access to your home. But adding a cat flap your composite door requires knowledge and knowledge of the door's construction. Any structural modifications can compromise its integrity, and affect its thermal performance. Install a cat flap on a composite door A cat flap allows your pet to come and go out and in the house without letting any other animals or cats