Looks like a Smith Enterprise Vortex; they just won in court (July 24th)against the US Army for a contract to FN who copied the same flash hider. Probably Dlask stopped making them to avoid any patent infringement.
Turns out that SEI supplies the Vortex to the Canadian Armed Forces on the C8 and C9 according to their website: http://www.smithenterprise.com/index.html
I've got one of their Good Iron Muzzle Brakes, the M16/M4 type (p/n 1002) and it does reduce recoil and allow you to stay on target much better; I'd buy one for the CZ if they made them. I'd buy one for the M14 if they weren't over $100US; those export laws you know....