Review on 🐱 CEESC Cat Flap Door Magnetic Pet Door: Lockable Access for Cats & Kittens, Multiple Sizes & Colors (L- Inner Size: 7.08"(W) x 7.48"(H), White) by Joe Whitman

First, I sincerely recommend that you remove the door. Not necessarily, but it makes the job MUCH easier. I installed it in the hollow door leading to our basement to keep the air conditioner from dripping down the steps. We have an older cat and like most, we are a little wary of new things. That's entirely justified, knowing that everything new is specifically designed to kill them. I first cut a hole in the door and let it go for a few days and then mounted the frame. I pulled the valve off which was easy and once she has had some time to get through the hole I will try to put the valve back on. I don't really need a lock feature but this one had one and had the best price and reviews. INSTALLER TIP: The long screws are too short for a standard cavity door. The instructions seem a bit odd as you have to insert screws from both sides and I assume they have to engage the threads of the screw coming from the opposite side? Do yourself a favor and buy 4 #8 x 2" screws. You'll thank me for that.