These Tacticool22 lightweight, aluminum construction S&W M&P15-22 Free Float Handguards are highly-engineered handguards that fit tightly against the receiver, eliminating the gap between the receiver and the rail. Features a top Picatinny rail at the front and rear of the handguard, and M-LOK accessory slots. Free float design M-LOK Internal Diameter: 1.36a ^2 Barrel nut included, with no timing or shims required. Anti-rotation tabs built into handguard. Mfg: Tacticool22