https://zenwriting.net/cablecr....edit03/replacement-u
Introduce your cat to the flap before it's installed so they can be familiar with the size and shape. Unlock the flap and let your cat explore it from every angle. Ensure the cut-out is even and square. Mark the screw holes and align them with the cat flap opening. The distance between the edges should be equal. Preparation Installing a cat flap in your home is beneficial for the well-being and health of your pet. It allows your pet to move from inside to the outside, without having let them in or leave. It