Ideal Pet Products Lockable Cat Flap Pet Door

This sturdy door gives my cat complete freedom to go into his spacious Catio whenever he chooses, day or night and he learned to use it very quickly. Highly recommend!

Easy to install, great price, and works really well.

This suited my needs. I needed a small cat flap. One of my cats is more than 12 pounds but he fits! I don't have it set in a door as for a window which I can't open very wide, so I just have the flap, a piece of plexiglass, and a bit of weather stripping. It goes out to an enclosed terrace, so it doesn't have to be great -- just good enough to use during heating season and air-conditioning season. The issue I have with it, is it does seem a bit flimsy. I was using a manual screwdriver and had some trouble getting the 4 screws in. One of screws actually cracked the plastic piece it went into, but only slightly. This could have been worse with an power screwdriver and less control. I am keeping it in the open position so cats can come and go. But I've seen cat doors like this before (I do some cat sitting) and I know that sometimes the levers don't work too well and if you futz with them too much you might have trouble keeping the door "unlocked" and easy for your cat to open. It should be noted that this is NOT one of those fancy doors that can only be opened by a cat wearing a special collar, and if it is "locked" it is locked on both sides. It works for me, but if I was looking for a sturdy cat door especially to an exterior space, I might look for something more substantial. It will work for a small or medium sized cat, but definately not a cat of size.