High quality handguards from Bowden Tactical. 100% made in the USA with US sourced materials. Barrel nut does not need to be timed. Solid mounting system that will not move under extreme conditions. 1.3 inch I.D. will accommodate most low profile gas blocks. We have seen some interference with some clamp-on style low profile gas blocks. Black Hardcoat Anodized Aluminum. MLOK slots at the 3,6 and 9 positions are manufactured to MAGPUL standards to ensure proper fitment with any MAGPUL certified accessories. Every handguard comes with a 4140 pre-heat treated steel barrel nut that has been nitrided not phospahted. All mounting hardware is included with full mounting instructions. A two inch long barrel nut ensures rigid mounting for rock solid accessory mounting. This system will not work with piston driven rifles. American made from American sourced 6061 T-6 extruded aluminum. 100% Made in the USA.