ALUMINUM, BRASS, CAST IRON, MILD STEEL, METAL, STAINLESS STEEL CUT MATERIAL; BI-METAL BLADE MATERIAL; 1-1/8 INCH DIAMETER; 450 RPM (ALUMINUM), 400 RPM (BRASS), 200 RPM (CAST IRON), 150 RPM (TOOL/STAINLESS STEEL), 300 RPM (MILD STEEL) SPEED RATING