Kit machine reamer 2 H7 - 3 H7 - 4 H7 - 5 H7 - 6 7 - 8 H7 - 10 H7 - 12H7. Reamer with left helix and right cut which acts as an Achimede screw to promote lubrication and cooling and also to push the chips forward and not scratch the part of the hole already reamed. Reamer recommended for obtaining a flawless finish in through holes.