● With Gauge block, it can be measured or corrected the accuracy of angle. ● Suitable to use on large tool maker vise with varied angle. ● Can be used to do many different accuracy of work. ● Material: YK30 ● Harden: HRC56°-58° ● Parallelism is within 0.003mm. ● Squareness is within 0.005mm. ● Weight:1.6kg