Irwin Blue Groove Power Bit Sets - IRWIN 10507764, These Blue Groove wood drill bits have a 6x faster penetration than a standard flat bit. Each bit has been fully heat treated for extra durability. The Tri-flute tapered flute design gives faster chip ejection and less binding during use. IRWIN 10507764 Blue Groove Power Bit Set (20, 22, 25mm)
