Mitutoyo 516-931-26CAL Steel Rectangular Micrometer Inspection Gage Block Set with  Calibration, Inch, Optical Parallel, 0.0625"-2.0" Range (9 Blocks), Meets ASME Grade AS-1 Specifications Calibrated gage block set of nine rectangular blocks measuring 0.0625" to 2.0", for use with the Mitutoyo Micro Checker (sold separately) to inspect micrometers Blocks (0.0625", 0.100", 0.125", 0.200", 0.250", 0.300", 0.500", 1", and 2") are constructed of high-carbon, high-chrome steel for durability and to minimize length changes Comes with optical parallel (0.5" thick) for inspecting parallelism and flatness of measuring faces Meets ASME B89.1.9 standards, grade AS-1, for dimensions and parallelism Includes a Mitutoyo Certificate of Calibration that the tool has been calibrated, and meets the International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) 17025 International Standard for testing and calibration laboratories