Irwin Speedbor 6-Piece Spade Bit SetBlue Groove point and cutting edge for faster chip removal. Double cutting spurs scribe the outside of the hole reducing breakout. 10% larger shank for added durability. Grooved hex shank prevents slipping in drill chuck or bit extension. Bit identification is simple with easy to read size markings. Standard length. Includes sizes: 3 8', 1 2', 5 8', 3 4', 7 8', and 1'.