https://king-wifi.win/wiki/Cat_Flap_Fitters
It is possible to put a cat flap in a upvc door panel or double glazing glass sealed units, although the best option is to purchase a brand new glass pane with an already-made hole. Follow the directions included in the kit. Make sure that the illustration accurately depicts the shape (circle or square). Safety If you have a cat or dog and want to let them into the garden without opening the door A microchip activated pet flap in your door panel made of upvc is a great choice. This will only let your pet in, preventing other animals and pests