made of HSS 4241 black chamfer drill bit body material: #45 steel single flute edge chamfer 90 degree heat treated and tempered high carbon steel with the titanium nitrate coating for superior cutting power using on steel, aluminum, plastic and wood. The drilling length can be adjusted for different situations simply by loosening and tightening the screw. Dimension: 3mm (Dia) x 60mm (L) 4mm (Dia) x 75mm (L) 5mm (Dia) x 85mm (L) 6mm (Dia) x 93mm (L) 7mm (Dia) x 10mm (L) 8mm (Dia) x 11mm (L) 10mm (Dia) x 12mm (L) Features: 1, Made of HSS 4241 drill bit 2, Drill body with Black Chamfer: #45 steel 3, 90 degree single flute edge chamfer 4, heat treated and tempered high carbon steel with titanium nitrate coating for superior cutting power 5, Using on steel, aluminum, plastic and wood. The piercing length can be adjusted for different situations just by loosening and tightening the screw, Note: The data is all manual measurement, please allow 1 - 3cm error, due to the difference of light and display, there will be a certain color difference, depending on the physical object received Delivery Quantity: (according to the main image)