I wanted to replace a cat door that was fitted through a wall. We got 'visitors'. I enquired about this and was assured by someone on the phone that it was a straight swop. I bought the part as I was told. IT DID NOT FIT. I telephoned the company, to be told it never would fit!! Fortunately I have a very handy husband who has altered it and made it fit. No help from the company, and my cat has difficulty using it, as the magnet has to touch the plate to trigger it to release, and then it shuts off again very quickly. My cat is a little slow and cannot push the door quickly enough. Not a good purchase.