Aero Precision Enhanced M-LOK (EM) Handguards provide a lightweight free float design for your custom M5 .308 build. The M-LOK system allows advanced modularity past the current 1913 picatinny rail system. Machined to mil-spec dimensions and engineered to perfection, this handguard eliminates bulk while retaining strength and stability. Are you attaching this handguard to a standard threaded upper receiver? Aero Preciaion handguards use the BAR interface and do not work with a standard barrel nut. If you are using their M5E1 Enhanced Upper Receiver, no additional pieces are needed. Features: One-piece free float design Built in anti-rotation tabs Scalloped rails 1.78" inside diameter fits most muzzle devices and 1.5" suppressors Compatible with low profile gas blocks DPMS High Profile (.210) Tang Quick disconnect sling socket at the 3, 6 and 9 o'clock positions Additional milling along flats to aid with gripping and add visual appeal New profile for the continuous picatinny top rail NOT Included barrel nut, shims, and screws to fit DPMS/Aero AR10 receiver threads