Fortis Manufacturing, Inc. Takedown Pin Set, Fits AR-15, Nitride Finish, Black Color PINS-TDPIV-BLK The Fortis Enhanced Pins Set features a drill through design to keep the weight low without sacrificing rigidity. Manufacturing it out of 17-4 stainless steel allows Fortis to balance between form and function. This enhanced set is machined with precision technology giving you tight tolerances between your firearms.