HSS 4241, STRAIGHT FLUTE, TRIANGLE SHANK, SURFACE: NITROCARBURIZING, SET INCLUDE: 4-12MM (4-6-8-10-12; OVERALL LENGTH: 64MM, WORK LENGTH: 43MM, NUMBER OF STEPS: 5), 4-22MM (4-6-8-10-12-14-16-18-20-22MM: OVERALL LENGTH: 74MM, WORK LENGTH: 52MM, NUMBER OF STEPS: 10), 6-38MM (6-8-11- 14-17-20-23-26-29- 32- 35- 38MM: OVERALL LENGTH: 100MM, WORK LENGTH: 76MM, NUMBER OF STEPS: 12)