These are the Generation 2 Mod 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. The pins are stainless steel pins. End retainers are black oxide, dark earth, or OD green. 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 Allen wrenches included. No modification to gun required.