The 900-375 Hardness Tester, 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 Twin Rockwell/Superficial Rockwell hardness tester is ruggedly engineered to obtain highly sensitive and accurate readings. Conforming to ASTM E-18 Rockwell hardness standards, 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.