I have a bunch of these in various colors but I'm not sure who made them. They were used as a roulette wheelcheck on a cruise ship (can't remember which off hand). They feel great, have sharp edges and are not slippery at all. They almost have a slight rubber feel to them. They are 40mm, the inlay/label is slightly textured. I took a label off to show the interior, revealing a metal disc with a spot weld in the center. Anyway, would love to find out the maker of these.