The SI Anti-rotation/Anti-walk pin kit adds an extra degree of security to prevent your pins from walking out under fire or harsh use.  Toolless installation and disassembly allows for ease of maintenance, with no small screws to back out or become lost.  The smooth polished surface allows for a smoother trigger pull with standard trigger groups, and the additional retention is essential for drop in trigger packs.  QPQ nitrided high strength steel prevents corrosion and wear providing for a lifetime of use.