Irwin SPEEDBOR Speedbor Flat Bit Patented micro-groove cutting edge and spurs produce a smoother hole finish. Double spur design scribes the hole before the chips are made, producing a cleaner hole and reducing vibration. All bits have a 1/4" hex shank that fits all drills and 1/4" quick change adapters. Blue-Groove point and cutting edge for faster chip removal - 4x faster than standard spade bits. Double cutting spurs scribe the outside of the hole reducing breakout Pack of 1