The Generation 2 Mod 3 pin sets by KNS Precision are for the POF GEN 3 & 4 Receivers and MAY fit other receivers with ambidextrous bolt releases. They are the strongest pins that can be produced and were designed to withstand the high impact of full and semi-automatic 9mm and suppressed .223/5.56 weapons. Stainless steel trigger & hammer pins are black nitrided. End retainers are black nitrided. Special anti-creep retainers prevent wear on your AR-15 receiver. Pin installation tool & 2 Torx wrenches included. No modification to gun required. Note: The torque spec on the screw is 11 inch/lbs. maximum. The manufacturer recommends 8 inch/lbs. of torque. The external width of some AR receivers may vary in the trigger/hammer pin area depending on the manufacturer. The pins being slightly too long will not affect the function or performance. Palmetto State Armory is your top choice for tactical accessories and gear from Fab Defense and other top manufacturers!