Ideal for drilling, enlarging or de-burring a precise hole into thin materials such as alloy and non-alloy metals up to a thickness of 4mm. Titanium Nitride (TiN) coating to reduce friction and prolong life High quality M2 Grade High Speed Steel (HSS) 3 flat shank to prevent slipping in the chuck Drilling diameter clearly marked on steps of drill for easy identification" Diameter mm: 4,6,8,10,12 Shank Dia. mm: 5.8 Shank Type: Three Flat Material: M2 Grade HSS Steel To Fit Screw Dia. mm: N/A Timco Step Drill (Size 4-12mm - 1 Each) in Gold