I've got a couple sets. These are made with Vigma's polymerized resin compound known as Kobo resin. I'm not sure if they use other resign compounds on their other sets. You'd have to check their website (www.vigma.com). I don't play with these much at all but they do play fine. The Zig Zags are no longer in production so it's unlikely I'll knock those around.Vigma balls any good? $900 dollars for a set is a lot!