Model Number: AKB1012Shank Diameter: 3mm, matching standard collets for most mini rotary tools (such as Dremel or INGCO MG13328, MG2008, and CMGLI12011 models).Material: Pink aluminum oxide (mounted abrasive stones), ideal for sharpening, deburring, and general-purpose grinding on metals, castings, welded joints, rivets, and rust.