Specific 3/32 inch ( 2.35 mm ) shank fits rotary tool, drill, grinder, hanging mills, etc Jewelry burr are made of premium Steel with high hardness, hard-wearing and anti-rust. Jewelry engraving bits bud burs includes 6 sizes: 008. 010. 014. 018. 020. 023 For carving of silver, jewelry, aluminum, walnut,olive core, beads, precious soft metal and more, Weight: 0.01984160358 pounds, Manufacturer: tiyao