10 percent larger shank for added durability. All bits have a 1/4 inch Hex shank that fits all drills and 1/4 inch 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. Double spur design scribes the hole before the chips are made, producing a cleaner hole and reducing vibration. Fits all standard quick change chucks. Grooved Hex shank prevents slipping in drill chuck or bit extension. Patented micro groove cutting edge and spurs produce a smoother hole finish.