https://fakenews.win/wiki/How_....to_Install_a_UPVC_Do
A skilled cat flap fitter will set up your pet's door inside a door or the wall. The wall-mounted version is more secure because an intruder won't be able to get through. It also reduces energy costs and helps to prevent draughts. The Tasker will mark out the position of the cat flap in your door, and then make the corners of the frame. They will also sand down the edges of the frame to give it a smooth finish. Microchip cat flaps A microchip cat flap is a simple and effective method to keep your pet safe in your home