Mitutoyo Steel Rectangular Gage Block Set, ASME Grade 0, 0.05 - 0.95" Length (81 Blocks) Grade 0 gage blocks supplied with a Mitutoyo certificate of inspection that the blocks meet American Society of Mechanical Engineers (ASME) B89.1.9 High-carbon, high-chrome steel provides high hardness and wear-resistance Rectangular shape for accurate wringing Nominal length (in inches) indicated with laser-etched, black characters Identification number etched in block for traceability