When I first moved into this 77 year-old house, which has the old-time framed-in matal screens held in with a hook, I thought that such a simple system was nearly cat-proof. Yet, one day I came back from grocery shopping and founD Tiger, Tiara, and Otis all outside. I thought to myself, " I don't remember letting them out". Tiger had figured out that if she jiggles the hook, then the screen will open, then she can get outside. (smart kitty) Since then I have repaired those possibilities of them getting outside again

......................wayne