The ceramic plates of air valves against abration, corrosion, dust, dirt, and sand. One dynamic plate and one stationary plate are made of extremely hard aluminum oxide . The flatness of seal face is 0. 10μm.

★ Good corrosion resistance, chemical reagent will not cause damage to it, can bebarehanded inuse  without anti rust treatment, for research of gauge block can be placed for a long time. In addition in the custody also does not need special treatment.
★The material of high hardness, abrasion resistance, service life is 5-10 times the steelgauge block is 4-5 times, hard alloy gauge.
★The material has good stability, no change, it can prolong the period of verification.
★The material is fine, smooth surface, grinding force, high precision.
★Linear expansion coefficient and common steel materials are similar, can replace the metalblock, and measuring the length of steel and iron products without temperature correction.
★ Mark using the most advanced laser engraving technology, pulse penetration, legibility,never fade.