Specifications:  Product Name: 5Pcs HSS-Co Twist Step Drill Bits;  Material: HSS;  Color: Cobalt;  Small Blade Length: 18mm;  Type:  8-4mm;  9-5mm;  10-5mm;  10-6mm;  12-8mm;  Quantity: 5Pcs× Cobalt Twist Step Drill Bits.     Features:  - Suitable for wood, stainless steel, cast iron, copper, aluminum-plastic profiles and aluminum alloys;  - Suitable for step punching of all kinds of sliding doors and plastic steel windows, all kinds of cast iron, countersunk screws;  - Standard 18mm small blade, sharp and durable, not easy to break, and will not have burrs when used on various types of wood;  - Adopt new technology for quenching, aluminum alloy does not stick to the knife.     Package Included:  5Pcs × Cobalt Twist Step Drill Bits    Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-YJL official store