Size - 12pcs mini chainsaw chain sharpener, 3/16" 4.8mm diameter, 22mm grinding head length, 3mm shank dia.Material - Diamond coated steel, high hardness and durable, excellent grinding effect with long service life, not easy to wear off.Application - These grinding heads are good for chainsaw teeth sharpening, also for metal surface polishing, wood and jade shaping, electric saws, glass, steel, and more.Feature - The chain grinding bits are easy to install, used with an electric grinder to easily sharpen your saw chain.Note - With finely and evenly diamond grains on the drill bit, the chainsaw grinding file is also suitable for high-precision work.