3 mm (1 or 8 in) diameter Mandrels will fit most rotary tools Stem: 1 or 8 inch (3 mm), length: 8 or 5 inch (40 mm) Professional Tool: There are 20 different shapes and sizes of rotary cutters, you can choose different types of cutter heads according to work needs 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 do carving and engraving work for jeweler, hobbyist, craft makers, model makers, etc 20 Pcs HSS Rotary Burrs with 1 or 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 softwood carving and milling. The treatment effect of hardwood is relatively weak, such as walnut, bodhi root, etc. Do not use as much as possible. Package Contents 20PCS X Dremel Wood Milling Cutter