Please be aware of which size you are purchasing. The most common size for standard AR15 lowers is .154. These are .155 in diameter.
These are the Gen 2 Mod 2 pin sets with Black colored side plates. KNS pins are the STRONGEST pins that can be produced and were designed to withstand the high impact of full and semi-auto 9mm and .223 suppressed weapons. The pins are stainless steel pins. End retainers are black oxide, dark earth, or OD green. Connectors have phosphate finish. 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.
The .1555 dia. pin is for worn receiver trigger and hammer pin holes. Being non-rotational, further wear is eliminated. They will also fit new receivers and will remove the free-play in match triggers.
The .1555 will not fit Jewell Trigger System.
For Rock River National Match triggers use the .1555 only.
There is no strength difference between the Gen 2 and Gen 2 Mod 2 sideplates. The only difference is cosmetic.