The non-woven synthetic fibre of these discs is coated with grains of Aluminium Oxide. They fix firmly to standard backing pads, using the “hook and loop” system. (We also sell the backing pads for these, please see our other items.) The open structure means that they are very resistant to clogging and therefore long-lasting, with less heat build-up than the traditional cloth or paper backed discs. For use on a wide range of materials, from wood and plastic to metals. They are particularly good for removing rust, cleaning up welds and finishing stainless steel and alloys, where their flexibility comes in handy.