Product Features This zirconia flap disc is made with premium zirconia grains that are resin over resin bonded onto extra strong polyester material as well as strong fiberglass backing system T29 flap disc construction with fiberglass backing plate effectively absorbs vibrations without smear during usage, bring more stable & efficient grinding Suitable for weld grinding, deburring, rust removal, edge grinding The Best Grinding Tool These flap disc are designed to provide the best grinding experience for the end user. Each flap disc has 72 emery cloth, and the removal rate of this disc is much higher than that of similar disc. Durable Materials Zirconia alumina materials are characterized by high toughness, fine grain size and good wear resistance. Widely Used in Grinding This flap disc set is ideal for grinding, mixing and removing various metals, non-ferrous materials, glass fibers, plastics, wood and other materials on uneven surfaces. Product Features: 1. Flap discs uses high-quality zirconia as its raw material for excellent wear resistance and durability. 2. Compared with alumina material, zirconia abrasive can carry out more powerful cutting and its longer service life, can greatly reduce the use of cost. 3. The zirconia flap disc sanding grinding can used for fast and durable cutting and finishing applications. 4. Flap discs can be applied to stainless steel, or can be milled and polished on mild steel or metals. Product Information Diameter: 4-1/2 inch Arbor Hole Size: 7/8 inch Abrasive Grit: 120 Maximum Rotational Speed: 13300 RPM