The BAUER™ 4-1/2 in. x 7/8 in., 40-Grit, Type 27 Flap Disc is constructed with high-quality Zirconia Alumina grain that lasts longer and gives better results than Aluminum Oxide alone. Flexible flap plates are ideal for grinding and blending on curves and contouring. This disc delivers high performance on carbon steel and stainless steel applications.