The wide construction of the NEMO 556 handguard provides superior heat shielding as well as the ability to accommodate custom builds with suppressors. - Caliber: 5.56 NATO - Height: 1.216 in (bore centerline to top of rail) - Length: 15 in - Exterior Width: 2.22 in - Inner Diameter: 1.83 in - Large inner diameter accommodates many under guard suppressors (1.83 in) - M-LOK slots at 36 and 9 oclock positions accept M-LOK compatible accessories. - Integrated rail at 12 oclock with engraved T-marks - 6061-t6 aluminum alloy extrusion - Mil-Spec hard anodize type 3 (black) - Integrated rotation limited steel quick disconnect sling mounts - 7075-t6 aluminum barrel nut type 3 hard anodize (1.25-18 thread) - Innovative mounting system provides a rigid and lightweight solution - Stainless steel fasteners and retainers ensure corrosion resistance - Utilizes a common T-15 wrench (Not Included) - Purple thread locker recommended (Not Included)