About this item Material: This carbide burr set/rotary bit set is made of premium tungsten Carbide steel which has long working life, Shank diameter: 3 mm(1/8 inch), Cutting edge diameter: 6 mm(1/4 inch), Please check the size before you buy it. Multi-Purpose: This rotary burr set includes everything you need for carving, engraving, polishing and removing sharp edges, being suitable for wood, stone carving, metal working and die grinders. The kit includes a massive selection of shapes for all types of cuts. Great Processing Quality: with this burr set, the surface of your target is smooth after carving or engraving, therefore it can even process a variety of high-precision mold. Those carbide burr rotary bit is generally use with handheld electric or pneumatic tool drive (can also be used in machine tool). The speed of the electric or pneumatic tools usually is 6000-50000 revolutions per minute. Full Customer Satisfaction, If youҲe not 100% satisfied with your purchase, please get back to us, we will offer refund or replacement to make sure your full satisfaction.