H S Precision made the first of them in the mid 2000's followed a bit later by Bell and Carlson. These were somewhat traditionally styled. The other less classically styled 2012 -13 or so stock I'm not sure who made them. I believe that Bell and Carlson still offer the original version. I have one of the original H S and one of the Bell and Carlson both on 527 Varmints in 223 Remington and they both seem to be the same quality wise. The HS stock has an HS Precision marked butt pad and I think the Bell and Carlson has an unmarked butt pad. Supposedly HS had some trouble supplying enough stocks for CZ quickly enough, so CZ-USA then contracted Bell and Carlson. Don't know if that's actually true or not, but that was the scuttle butt back in the day.