Applications: The surface use scratching technology and it can be used in any kinds of testing work and can measure parts precisely .At the same time ,it can be used to test and measure benchmark, test parts' size precision and deviation and scribe lines.The feature s of it are high precision and wear-resistant. Material:Made from closed grained cast iron of HT 200-300 . Hardness between 170-240 BHN Two times manual processing (Artificial annealing 600 ℃-700℃ and natural aging about two or three years)make the precision more accurate. Precision: Generally as per JB/T7974-99.Flatness accuracy as per Gr0 ,Gr1,Gr2,Gr3 of JB/T7974-99 Spercification: 300mm-3000mm(we can produce and process these products according to the customers’ drawings or requirements) contact person:Sophia Han tel:0317-4505966 msn:zhongbozg@msn.com