Faithfull Mini Grinding Wheel Assortment contains 50 assorted miniature grinding wheels with 1/4in shanks for compatibility with most electrical and cordless drills. They are ideal for sharpening and grinding steel, and have points ranging from 15mm to 25mm in diameter. The profile options are three versions of both conical and cylindrical and two versions of both pointed and rounded. 15 x Conical (3 sizes: 5 of each size) 15 x Cylindrical (3 sizes: 5 of each size) 10 x Points (2 sizes: 5 of each size) 10 x Rounded (2 sizes: 5 of each size) SAFETY TIP Faithfull grinding wheels are for use in power or cordless drills only and are not suitable for use in die grinders or high-speed air tools.