NIST traceable. Certified to meet the requirements of ASTME-10. Made from highest quality material to ensure the most uniform and repeatable blocks available. Scale and general hardness range should be submitted to us with your purchase order for these blocks. A traceable calibrated test certificate is supplied with each test block. The test results will conform to the appropriate ASTM standards designation (E10, E18, E384). Special test blocks available upon request. Specify scale and range.