ALUMINUM, BRASS, CAST IRON, MILD STEEL, METAL, STAINLESS STEEL CUT MATERIAL; BI-METAL BLADE MATERIAL; 3 INCH DIAMETER; 170 RPM (ALUMINUM), 150 RPM (BRASS), 75 RPM (CAST IRON), 55 RPM (TOOL/STAINLESS STEEL), 115 RPM (MILD STEEL) SPEED RATING