Twin Rockwell/ Superficial Rockwell hardness tester. Model No. 900-375A. Features. Reads in all Rockwell Hardness Scales and Superficial Rockwell Hardness Scales. These include the popular HRA, HRBW, HRC, HRN and HRT Hardness scales. Direct analog dial reading. Advanced design, easy to operate. Engineered to obtain highly sensitive and accurate readings. Perfect for laboratories, workshops, tool rooms, inspection labs, etc. Test Rockwell and Superficial Rockwell Hardness in 1 Unit!. Our latest Phase II analog Rockwell Hardness Tester, the 900-375, tests both Rockwell hardness and Superficial Rockwell hardness in one unit, with state of the art design and dynamic precision only found at Phase II. The Phase II is ruggedly engineered to obtain highly sensitive and accurate readings. Utilizing the guidelines of ASTM E-18, this hardness tester will offer unmatched repeatability in all Rockwell hardness scales. A perfect performer suited for any environment including heat treatment facilities, tool rooms, workshops, laboratories and inspection labs. Lifetime technical support is included with all Phase II Hardness Testers. So test away with confidence and a level of accuracy you will only find at Phase II.