https://scientific-programs.sc....ience/wiki/Cat_Flaps
A cat flap made of UPVC allows your cat to leave and come as they please. The installation is a 3-step procedure that can be completed on glass doors, wooden doors panels or UPVC panels. This is an excellent option for those who wish to secure their pets and reduce energy costs. UPVC panels can resist heat, moisture and UV. Easy to install Installing a pet flap on your glass panel or door is an excellent idea if have a kitty. This is a great way to keep your pet safe while you are away. There are many different designs