Measure the  distance of diameter,roundness, taper with parallel surfaceSuper wide positioning bridge insure that centre in the center of hole automatic

 Order No          Range            Resolution       5306-10                   6-10mm              0.01mm         5306-18                 10-18mm              0.01mm         5306-35                 18-35mm              0.01mm           5306-50                 35-50mm              0.01mm           5306-160               50-160mm             0.01mm5306-250               160-250mm           0.01mm5306-450               250-450mm           0.01mm

The gauge is in testing by our special testing machine: