Portable Rockwell / Superficial Rockwell / Brill & Rockwell Hardness Testers. The principle and structure of this device is in accordance with ASTM E110. Meeting the requirement of ISO6508/6506 and ASTM E18 / E10. Designed to the basic principle of Rockwell hardness test. The test force is apply by screw and a calibrated U-sharp spring. Two indications are installed on the tester. One is Dial indicates the force value by measuring the deformation of the elastomer, and one precision screw micrometer used for testing the indentation depth