AR15/M16 Gen G Non-Rotating Trigger/Hammer Pins .1550 Diameter, 4140 Steel, 45-48 RC. These are the Generation 2 pin sets. They are the STRONGEST pins that can be produced and were designed to withstand the high impact of full and semi-automatic 9mm and .223 suppressed weapons. They will also fit the .308 AR rifles. The pins are stainless steel. End retainers are black Nitride or dark earth. 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. Pin installation tool & 2 Torx wrenches included. No modification to firearm required. THE TORQUE SPEC ON THE SCREW IS 11 inch/lbs. MAXIMUM. We recommend 8INCH/LBS of torque.