Mercer 342120 is a 120-Grit 4-1/2 X 7/8-Inch Zirconia Type 29 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 342120 120-Grit 4-1/2 X 7/8-Inch Zirconia Type 29 Flap Disc