FOTAR also used the Vapla round beveled edge lens board design, but a different OD size. Not interchangeable without mods.

I was about to make a few from high grade plywood, but found 4 on eBay and bargained the seller down.

If you have a Vapla with a big enough hole there are many ways to just drop a lens in the hole with almost any other lens board and gaff tape the lot.