https://click4r.com/posts/g/18....043464/cat-flap-cove
Are you fed up with having to get up and down to open the door for your pet? A cat flap may be the answer. Pet-flap fitters can put them into any kind of door including uPVC or composite doors. They can also be fitted into certain types of walls. Security Cat flaps are often installed on doors, but many also have them installed on windows or double-glazed doors. If you don't have a wooden wall or door installing one into glass is a great idea. It's an excellent option for those who rent. You'll require a glazier to install