ALUMINUM, BRASS, CAST IRON, MILD STEEL, METAL, STAINLESS STEEL, WOOD CUT MATERIAL; BI-METAL BLADE MATERIAL; 1-1/2 INCH DIAMETER; 345 RPM (ALUMINUM), 300 RPM (BRASS), 150 RPM (CAST IRON), 115 RPM (STAINLESS STEEL), 230 RPM (MILD STEEL) SPEED RATING