Irwin 88887 Speedbor 13 Piece 1/4-Inch to 1-Inch Spade Drill Bit Assortment with Rack Includes 1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8, 15/16, and 1" and rack Patented micro-groove point and cutting edge with extended spurs For all 1/4" and larger electric drills Bores two times faster, lasts three times longer 13 Popular Sizes