Features: 4140 Heat Treated Barrel Nut Barrel Nut and Wrench Included Features Patented 4140 Heat Treated Torque Plate 6061 Aluminum Type 3 Hard Coat Anodized Continuous MIL-STD 1913 Picatinny Top rail Two Integral Anti-Rotation QD Sling Sockets Super Slim 1.5" Outside and 1.3" Inside Diameter Seven Sides of M-Lok 5-Slot Polymer M-Lok rail included Fully Dehorned and Deburred 100% Made in USA- Keeps America Working MI Lifetime Warranty 10.8 oz