Faithfull Step drills are used for cutting varying hole sizes in material up to 4 mm thick without changing the drill bit. Each drill cuts parallel holes within a specific size range, rising in 2mm increments.
Sizes are from 6 to 20mm. Increments of 2.0mm
Max thickness is 6mm
HSS Step Drill Bit 6-20mm. Also, made from HSS (High-Speed Steel)