Review on RIKOUNAN 4 Way Locking Cat Door - Quiet Pet Doors for Cats - Large Interior/Exterior Cat Flap Door - Easy Installation Premium Door for Cats & Small Dogs by Lindsay Siebert

I installed this cat door in a 0.2 inch thick plexiglass window that I installed in an existing window under the outer/top glass. narrow enough that I could still drop and block the inner/bottom panel. I had to cut off most of the collar and use the long screws provided, but they were too long so I had to cut them off. The door is fairly well insulated and keeps cold air out well and the magnet does the trick of closing it quickly for your cat. I have small cats but I went for the large size anyway and I'm glad I did made so they have a bigger one place. Only minor downside is that the transparent materials aren't as transparent as the plexiglass I used for the window and I think the kittens are already scratching it. Little problem.