Product Name: HSS TWIST DRILL BITS Material : HSS 4241 Process : Fully Ground Shank Type: Straight Surface Finish : Bright finish / Tin Coated / black finish Standard : DIN 338 Diameter : 1.5 - 6.5mm + 3.2 mm + 4.8 mm Features: The large increment of drill body makes the product not easy to break. The hole with thick core is easier. Quenching temperature within 5 degrees temperature control, more stable quality.