7 Piece 18mm Round Shank Indexable Boring Bar Set (1001-0718) ~ Negative 3 degree lead angle. ~ TCMT21-5, positive rake 90 degree lead with 7 degree relief, inserts fit all bars. ~ Made of 40Cr alloy steel. ~ Screw down style. ~ Includes C-6 inserts. ~ 18mm shank size. ~ Please see chart picture for sizing information. ~ Furnished with fitted aluminium case.