5/16" Irwin Straight Shank Carbide Tipped Masonry Drill Bit, 4-3/4" Overall Length, Carbide Tipped For Maximum Wear Resistance & Capacity To Withstand High Impact, Patented Flute Geometry For Faster Chip Removal, For Use With Rotary & Percussion Drills, Shot-Peened, Double-Tempered Finish For Extra Durability.