FeaturesCornerstone AR15 handguards provide an alternative to foreign sourced product. American made quality at import prices.American sourced 6061 T-6 extruded aluminum.Available in 7", 10", 13" and 15" rail lengths, in either Full Flat Top or Competition Top.An overall width of 1.5 inches and a weight of only 9.5 ozs (for the 15" model) provide ultimate comfort.A 1.3 inch I.D. will accommodate most low-profile gas blocks. Some interference with clamp-on style low profile gas blocks is possible.MLok slots at the 3, 6 and 9 positions are manufactured to MAGPUL standards. This ensures proper fitment with any MAGPUL certified accessories.Every AR15 Cornerstone handguard comes with a pre-heat treated, 2 inch length 4140 steel barrel nut. This ensures rigid, rock-solid accessory mounting. The barrel nut has been nitrided, not phosphated.Mounting instructions and hardware are included with every AR15 handguard.Available in Hard Coat Black anodized finish or in the bright.Hard Coat Black anodizing is in accordance with MILA-A-8625 Type III Class II specifications.100% warranty against all manufacturing defects.