I've got one I bought from Brownells. It's weird because I've never seen the same one posted on the forums. It's the same length as an A2 but also has the flash hiding tines. It's made to attach the NT-4 suppressor. I have it mounted on my 11.5 upper and it reduces recoil quite a bit, but when shooting at night, I'm told it has a huge fireball which can't be seen by the shooter.