The standard hardness block is the standard configuration for Mitech series Webster hardness testers. With size of 150×25×2(mm)and hardness of 15.5-16.5HW.It is mainly used to judge whether the measuring error of leeb hardness tester is in the permitted range by national standards or international standards. Each standard hardness block is engraved with the serial number and hardness values which are consistent with qualified certificates one by one, to ensure the traceability for the national standards or International standards. The standard block is specially made with plating harden layer process. With high quality material, its hardness value is stable and reliable. It is the necessary part for accurate measurement of the instrument.