Thanks, Aaron. That one looks like it would work, but it is totally different from the one I saw a picture of, somewhere.
The one I saw was a coarse metal mesh, with a slight convex shape, and was rounded. Slamm enough mesh that it looked like it could stop a b-b from an air rifle. but was robust, so if a big piece of anything hit it, it wouldn't distort much.
I'm gonna look around before I buy one, but I'm definitely going to buy one.