IRWIN 5026005 Masonry Bit Percussion Drill Bit, Spiral Flute, 8-11/16 in L Flute, Straight Shank, 1/4 in Dia Shank                   Nickel plated for fast, smooth performance. Carbide tip can be used for rotary drilling applications also for deep drilling. Slow spiral for quick and easy debris removal, 7/16 in and larger drill bits have reduced shanks.