Midwest Industries Mig4M15 Tactical G4M Handguard AR-15 Black Hardcoat Anodized Black 15' 6061-T6 Aluminum M-LOK This G4 15" One Piece Free Float Handguard Is M-LOK Compatible. It features a 4140 Heat Treated Barrel Nut And Torque Plate. It Has a Super Slim 1.5" Outside And 10.3" Inside Diameter. It Has a Continuous Mil-Std 1913 Picatinny Top Rail. 100% Made In The USA. Firearm Model: AR-15 Material: 6061-T6 Aluminum Finish: Black Hardcoat Anodized Rails: Picatinny Free Floating: Yes