2-1/4" Diameter, Speedbor Max Self Feed Wood Drill Bit, 3 Times The Cutting Area & Edges Of Standard Self Feed Bits, 7/16" Hex Quick Change Impact Shank Fits 1/2" Or Larger Drills, Also Fits 7/16" Hex Impact Wrench Drills, For Drilling Large Diameter Holes In Wood, Aggressive Screw Pitch, Precision Milled Shank Eliminates Run Out & Wobble, Forged In 1 Piece From High Carbon Steel For Max Strength Under Tough Drilling Conditions, Ideal For Pipe & Conduit Systems, Carded.