The 3 mm (1/8 in) diameter mandrels will fit most rotary tools; Shank: 1/8 inch (3 mm), Length: 8/5 inch (40 mm) Professional Tool: There are 20 different shapes and sizes of rotary burrs, you can choose different types of cutting heads according to the needs of the work Quality Material: The milling bits are made of quality high speed steel with long life, has the advantages of high hardness Ideal for woodworking and engraving; Works on metal, stone, wood, plastic, foam or resin Suitable for engraving, beveling, chamfering, grooving, reaming, hollowing. Used with rotary tool to perform carving and engraving work for jeweler, hobbyist, craft makers, model makers, etc. 20 Pcs HSS Rotary Burrs with 1/8" (3mm) Shank Fit for Dremel for Craft Projects and DIY Creations Features Material: High Speed Steel Size: The handle diameter is 3mm and the total length is 40mm Color: Silver Quantity: 20PCS Ideal for woodworking and engraving; Works on metal, stone, wood, plastic, foam or resin Product Instructions: This product is mainly used for carving and milling softwood. The processing effect of hardwood is relatively poor, such as walnut, walnut root bodhi, etc. Do not use as much as possible. Package Contents 20PCS X Dremel Wood Burr