Sincereetali Professional Kit: 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, they will satisfy your different craft creation needs. . Multi-function: Diamond drill bits have 10 different grinding bits for abrasion, carving, cutting, polishing and engraving. . Compatibility: 1/8 (3.1mm) shank, 39mm length, fit for dremel electric rotary tool and most mini grinder. User-friendly design and easy insertion process, incredibly easy to use. . Quality Material: The milling bits is made of quality high speed steel with long life, has the advantages of high hardness, good wear resistance and heat resistance. . Our Guarantee: We have confidence in our products. If you have any questions about the product, please feel free to contact us, we will give you a satisfactory answer within 24 hours. .