https://notes.io/w5WjE
https://jsfiddle.net/ca2Lmy7b/
Installing a cat-flap to your door is a simple procedure. You'll need to be aware of a few things before you begin. Upvc door panels that have the cat flap can be installed without having to cut a hole in your door or wall. They are available from a number of glass companies with a premade hole to fit a pet door. 1. Safety upvc door panels cat flaps are simple to install and can be adapted to different kinds of doors. They are energy efficient and weatherproof, and have an air-tight seal built-in to aid in insulating the openi