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.Features :Mil-spec size tolerance from .247-.2485Comes in either black nitride coating or case hardened finishLightweight at 0.34 oz combinedMaterial 17-4 Stainless SteelMade in the USA