The NSR Super Slim Handguard is slim, light customizable handguard available for the AR-15. The bare handguard without any additional rail sections mounted is only 1.48" in width. The continuous top rail allows you to mount iron sights, optics and any other accessories without additional rail sections. The KeyMod system allows users to customize the handguard with rail sections and direct mount accessories. The handguard is constructed of aircraft aluminum and finished black or FDE coat. The handguard is secured to a barrel nut with 4 T25 Torx fasteners. Installation requires a 1-1/6" crows foot wrench (not included) for the barrel nut; standard AR-15 barrel nut wrenches will not work with this handguard system. The NSR will work with Heavy Profile barrels and a maximum size of .875" diameter low profile gas blocks when located under the handguard. SwitchBlock equipped barrels will work, when the gas block location is outside of the handguard. This is rail system is not compatible with gas piston conversions.