Phase 5 Littleboy Hex Brake is a compact muzzle brake designed for 7.62x51 / .308 / 300BLK with 5/8-24 TPI threading. Length 2.5 in, width 1.26 in, weight 5.0 oz. Parkerized black finish. Includes one crush washer. The brake overlays the barrel crown by approximately 0.85 inches to maintain barrel accuracy. Package contents: Phase 5 Littleboy Hex Brakes and Crush washer. Variants include 7.62x51 / .308 / 300BLK (5/8-24), 5.56/.223 (1/2x28), and 9mm configurations.