ATHENA allows a shooter to inexpensively upgrade their rifle to the Dynamount Sighting System. Muzzle rise has been optimized as well, with gas vented at an angle then forward. This sends a lower percent of sound back towards the shooter, optimizing sonic performance over recoil. Like all Ultradyne muzzle devices, a timing nut is included for easy installation. Features: 5/8-24 thread pitch CNC machined 416 stainless steel Nitride finish Includes timing nut