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 creates a balance between form and function. This enhanced set is machined with precision technology giving you tight tolerances between your firearms. FeaturesMil-spec size tolerance from .247-.2485Lightweight at 0.34 oz combinedMaterial 17-4 Stainless Steel