Superior quality. This rotary burr set is made of HSS high speed steel for wear resistance and durability. 1/8 shank diameter. Shank: 1/8 inch (3 mm), Length: 8/5 inch (40 mm). 20 in one. Each bit is designed to fit a variety of angles or situations, to fit the tool and to meet most of your drilling needs. Suitable for engraving, chamfering, beveling, slotting, reaming and hollowing. High compatibility. This HSS carbide rotary kit features a 1/8" shank and can be used with most rotary tools or grinders. Ideal for working with a variety of materials such as wood, plastic, foam or resin models. High speed rotation. Speeds typically 6,000-50,000 rpm, long life, reduced inefficient rotation and stays sharp longer than cheap and low quality burrs. Wide range of applications. Carbide rotary burr sets are perfect for woodworking, carving, drilling, chamfering, beveling, slotting, reaming, shaping and gouging. Uses. 1. To provide micro holes or cut sections in various shapes. 2. Material lengths effectively handled around 40mm. 3. 20 piece set of milling cutters, including collets. 4. All 3 mm diameter collets are suitable for most rotary tools 5. These 20 HSS milling cutters are ideal for a variety of jobs such as model making. 6. Uses: stone carving, jade carving, grinding, polishing Specifications. Material: high speed steel Cutter pattern: single cut Colour: as shown Shank diameter: 1/8 (3mm) Cutting diameter: 1/8 (3mm) Overall length: 40mm Quantity: 20 pieces Package includes. 20 pieces of HSS rotary drill bits Caution. When using these bits the material can get very hot, please add some water or coolant to prevent the material from overheating during use.