4.5" Flap Disc has 40 Grit with a 7/8" Hole. Shape is Type 29 (conical). Flap Discs are made with quality blue zirconia and hold up to harsh conditions. Our flap discs provide long life with quick and efficient material removal. Flap Discs can sand/cut/grind these Materials: Metals, Stainless Steel, Aluminum, Cast Iron, Welded or Heat Treated.