Irwin 10506629 Blue Groove Flat Bit x8 Pc Set Irwin Blue Groove 4x 8 Piece Flat Bit Set with patented Bluegroove point and cutting edge designed to cut not scrape the timber for 4x faster chip removal. FEATURES Made of steel 1/4\" Hex shank prevents bit slipping in the drill Double cutting spurs scribe outside of the hole, reducing breakout Relief angle has been increased from 12° to 17° Parabolic scoop optimises control and removal of wood chips Thicker cutting edge for longer drilling life with 10% larger shank for added durability CONTENTS 1x 12mm x 157mm Flat Bit 1x 16mm x 157mm Flat Bit 1x 18mm x 157mm Flat Bit 1x 20mm x 157mm Flat Bit 1x 22mm x 157mm Flat Bit 1x 25mm x 157mm Flat Bit 1x 28mm x 157mm Flat Bit 1x 32mm x 157mm Flat Bit