The Mercer 332120 is a 120-Grit 4-1/2 X 7/8-Inch Zirconia Type 29 High Density Flap Disc. Conical shaped flaps are angled at 10 degree which is ideal for contour and edge work. Angled flaps provide greater surface contact for a more aggressive cut. Most efficient when used between 15 degree to 25 degree angle. High Density: 40% more cloth than our standard discs. Provide longer life, twice the removal rate, and a softer grind. Thicker design conforms better to irregular shapes. Features: * Fiberglass backing * Heavy X-weight cloth * Resin on resin bond * Available with 5/8-Inch -11 threaded hub * Fast and cool cutting What"s In the Box: * Mercer 332120 120-Grit 4-1/2 X 7/8-Inch Zirconia Type 29 High Density Flap Disc