Bosch Daredevil NKLT09 Auger Bits, 9/16-Inch by 17-1/2-Inch by 13-1/2-Inch Reinforced Tip: Withstands repeated nail hits Reamer edge: Improves entry and exit-hole quality Dual cutting edges: Provide easier nail cutting and balanced drilling Reinforced spine: Adds strength for heavy duty applications