Irwin 3043005 Speedbor Ship Auger Bits with WeldTecIrwin 3043005 Speedbor Ship Auger Bits with WeldTec Features:; SPEEDBOR with WeldTec Ship Auger bits are MADE STRONGER and LAST LONGER because a harder cutting edge is welded to the base material; 2X Nail Cutting Life compared to standard IRWIN ship augers; Patent Pending Welded Cutting Edge; Aggressive Screw Pitch; Wide Flutes; 7/16" Quick Change Impact Shank; Fully Forged Body on bits 3/4" diameter and larger.; Diameter: 1/2"; Overall Length: 17"; Shank Size: 7/16" Quick Change Impact Shank