Shark Industries Green Zirconia and Red Ceramic mini grinding discs target stainless steel/nickel alloys and other hard metals and heavy rust. The Green Zirconia provides longer life than aluminum-oxide, and is available in 36, 50 or 80 grit and 2" and 3" diameters. The Red Ceramic discs are available in 2" and 3", grits 36, 40, 50, 60 and 80, and are cooler running and more load resistant than the Green Zirconia.