Features: With its M35 cobalt speed steel construction, the professional twists drill set is perfect for drilling through stainless steel and other metals. Precise grinding process with smooth surfaces and high grinding accuracy; 135° SPLIT Point drill bit, sharp and durable cut edge, stable feed; Suitable for hand electric drill, electric drill, drilling machine, machining center, milling machine; Note: It can not use on tiles, concrete, wall, stones, etc; Specifications: Material:M35 Steel Option Type:10x3mm Diameter Drill Bits,10x4mm Diameter Drill Bit,10x5mm Diameter Drill Bit,10x6mm Diameter Drill Bit,10x8mm Diameter Drill Bit,5x9mm Diameter Drill Bit,5x10mm Diameter Drill Bit,5x12mm Diameter Drill Bit,5x13mm Diameter Drill Bit,5x14mm Diameter Drill Bit,5x11mm Diameter Drill Bit,10x1mm Diameter Drill Bit,10x2mm Diameter Drill Bit,10x7mm Diameter Drill Bit, Package Includes: Package A: 10xDrill Bits Package B: 5xDrill Bits note: Please allow 1-2cm errors due to manual measurement,please make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.