ALUMINUM, BRASS, CAST IRON, MILD STEEL, METAL, STAINLESS STEEL CUT MATERIAL; BI-METAL BLADE MATERIAL; 4-3/4 INCH DIAMETER; 95 RPM (ALUMINUM), 90 RPM (BRASS), 45 RPM (CAST IRON), 35 RPM (TOOL/STAINLESS STEEL), 70 RPM (MILD STEEL) SPEED RATING