These are the Generation ST pin sets that were designed for the Spike's Tactical Compressor Rifle Series. These are the STRONGEST pins that can be produced and were designed to withstand the high impact of full and semi-auto 9mm, .223, and 7.62mm suppressed weapons. The pins are stainless steel. The custom designed end retainers are black oxide. An absolute must-have for all M-16 owners. They will also protect your AR-15. Special anti-creep retainers prevent wear on your irreplaceable M-16 or AR-15 receiver. No modification to firearm required. THE TORQUE SPEC ON THE SCREW IS 11 INCH/LBS. MAXIMUM. We recommend 5 INCH/LBS of torque.