Irwin 4935109 Multi-Material Jobber Length Masonry Drill Bit - 5/16" x 4-3/4"

Designed specifically for rotary drilling, but are tough enough to be used with hammer drills. Carbide tip has a unique diamond-ground, four-facet design with sharper cutting edges for centered starts with no walking, fast drilling, and excellent hole quality in a variety of materials. Double-milled flute ensures fast, efficient removal of drilling dust and debris to increase speed and prevent clogging. Compatible with all standard 1/2" and 3/8" chuck drills. Hole Size: 5/16". Flute Length: 3-3/4". Overall Length: 4-3/4".