Midwest Industries MI-CRLW15 AR-15 Free Float Hand Guard 15" Overall Length Lightweight Design With Slim Profile Barrel Nut, Screws, and Barrel Nut Wrench Included Features Patented 4140 Heat Treated Torque Plate For Simple Installation One Piece Free Float Design 9.7 oz Installed Weight Rugged 6061 Aluminum Type 3 Hard Coat Anodized MIL-STD 1913 Picatinny Top rail Two Integral Anti-Rotation QD Sling Sockets Super Slim 1.5" Outside and 1.3" Inside Diameter 4 Sides of M-LOK Slots 5-Slot Polymer M-LOK rail included Fully Dehorned and Deburred 100% Made in USA- Keeps America Working MI Lifetime Warranty Matte Black Manufacturer's Note:Due to the many different dimensions in BILLET UPPER RECEIVERS on the market, please contact your billet upper receiver manufacture to insure fit of this hand guard. This hand guard is compatible with standard forged upper receivers. NOT FOR USE ON GAS PISTON AR's!