ALUMINUM, BRASS, CAST IRON, MILD STEEL, METAL, STAINLESS STEEL CUT MATERIAL; BI-METAL BLADE MATERIAL; 2-1/8 INCH DIAMETER; 240 RPM (ALUMINUM), 210 RPM (BRASS), 105 RPM (CAST IRON), 80 RPM (TOOL/STAINLESS STEEL), 160 RPM (MILD STEEL) SPEED RATING