29 Piece 1/16-1/2″ By 64Ths Black & Gold Oxide HSS Drill Set ~ Premium high-speed steel withstands extended drilling in tough materials. ~ Black and gold oxide finish provides maximum corrosion resistance. ~ 135-degree split-point tip starts drilling immediately with less force and eliminates “walking” across the work surface. ~ USA made index case for easy bit access and identification. ~ Reduced tri-flat shank for sizes from 5/32″ to 1/2″.