Shank Dia*Bit Diameter: 3*3mm, 3*4mm, 3*5mm, 3*6mm, 3*7mm, 3*8mm. All shank size of 1/8inch (3 mm), universal chuck, allowing them to be compatible with most die grinders and rotary tools as you finish, grind, and shape your work with precision. Material: High-speed steelcommonly called white steel High hardness, anti-corrosion, heat-resistance, sturdy and durable. Three blades design: Accurate centering for sharp and precise countersinking, fast discharge chips from the hole on sides. Size…