This Dremel 8215 Grinding Stone Wheel is made of Aluminium Oxide and has a working diameter of 25.4mm. It is ideal for sharpening, deburring, and general-purpose grinding of most materials, including metals, castings, welded joints, rivets, and rust. The accessory features a 3.2mm shank diameter and a maximum RPM of 20000. It is compatible with Dremel rotary tools.