Machined aluminum handguard mounts onto your AR-15 and free floats the barrel to relieve stress and help enhance accuracy potential. Fits all standard size uppers and includes barrel nut for fast and easy installation. Accepts standard barrel nut wrenches and features knurled center section for secure grip. Rifle handguard has 5 longitudinal flutes to save weight, and 10 slots cut in the muzzle end to help improve air flow and help speed cooling. Carbine handguard has 8 longitudinal flutes to save weight. Pistol handguard has no flutes or slots. Mfg: Double Star SPECS: 6064 T6 aluminum, hardcoat anodized, matte black finish. 2"(5cm) O.D., 1 3/4"(4.4cm) I.D. Includes barrel nut. Rifle 12.5" (32cm) long, 13.1 oz. (371g) wt. Carbine – 7" (18cm) long, 8.1 oz. (229g) wt. Pistol 4" (10cm) long. 5.3 oz.(150g) wt.