20Pcs 120 Grit Diamond Burr Set Drill Bits Set for Rotary Grinding Tool Product Feature: Ball shape head, diamond grinding tools for diamond and jade carving. These are 120 grit and 3.0mm shank. Diamond burr tools for grinding, engraving, cutting lines, polishing, carving, glass engraving. Electroplated diamond grinding. Need to be used with electric mill/hanging mill/bench mill. Perfect for plastic, wood, glass, metal, ceramics, tile, marble, granite, stone, and many other materials. 20 Pcs different heads grinding bits are included, Various shapes and sizes. Product Specification: Material: Diamond Shank Diameter: 3mm The Head Diameter: 6mm Total Length: 45mm Particle size: 120 grit Package Included: 1 x Set Electroplated Diamond Grinding Burr Drill Bits(20Pcs)