Minimal-profile replacement for factory front sight/gas block won’t interfere with extended-length tactical forearms, while ensuring proper function of gas system for reliable cycling. Protrudes only .420' above barrel, covers less than 1' of barrel length, and adds only 1.4 oz. of weight. Compatible with M4-style carbines and M16A2/A3/A4-style rifles with any length, .750' O.D. barrel. Two steel setscrews keep the block securely anchored to the barrel to prevent shifting even under the force of full-auto recoil. Black oxide finish matches most factory barrel finishes. SPECS: Carbon steel, oxide finish, matte black. .950” (24mm) long. 1.375” (3.5cm) overall height. 1.4 oz. (41g) weight. Fits AR-15/M16 with .750” O.D. barrel at gas block mounting position. Includes hex-head setscrews.