ALUMINUM, BRASS, CAST IRON, MILD STEEL, METAL, STAINLESS STEEL CUT MATERIAL; BI-METAL BLADE MATERIAL; 2 INCH DIAMETER; 255 RPM (ALUMINUM), 230 RPM (BRASS), 115 RPM (CAST IRON), 85 RPM (TOOL/STAINLESS STEEL), 170 RPM (MILD STEEL) SPEED RATING