Description [High Quality] Tungsten Burr set, High Speed Steel, stay sharp longer than the cheap, lower quality burs [20 Different Bits] Each Burr is shaped to fit different angles or situations, fits Tool, meet most of your drilling needs [Diameter of Shank] Shank diameter: 3.12mm/0.12in, total length: 40mm/1.6in, high grade and the cuts of each bit make you feel that they have been designed with precision [High Compatibly] The Carbide Rotary Files can work with most small rotary tools for DIY carving fans [Wide Application] Carbide Rotatory Burr Sets are perfect for softest wood, carving engraving, drilling glass/holes 20pcs high speed steel carbide rotary burr in Assorted shape, fits most rotary tools can meet most of your needs, for drilling holes, engraving, carving, wood working High speed steel Features as solid, can last for longtime, not easy to get wearing Tips: The Cutting heads are not very sharp tools, work in the softest wood well: Shank diameter: approx 3.12mm/0.12in Total length: approx 40mm/1.6in Package Include: 20pcs Tungsten Burr set （meantion : 20pcs = 1 set）