I know there's a hundred threads/posts on this subject because I've read most of them. And I know there's all kinds of things used to install inserts in the playfield, but I don't remember seeing this one mentioned. I could be wrong...it wouldn't be the first time.
I have a playfield project I'm about to start and was looking for the 'perfect' blocks for installing inserts. These are 1" thick acrylic blocks in 3 different sizes. They're flat as flat can be, solid, and see-through. I just got mine and they're better than I was expecting. Here is the link if anyone's interested... amazon.com link »81l6jvzPvVL._AC_SX425_ (resized).jpg