This hardness tester with digital indicator comprises the very best in "state of the art” design coupled with dynamic precision only found at Phase II. The 900-331D Rockwell scale hardness tester is easy to operate yet engineered to obtain highly sensitive and accurate readings. A perfect, rugged performer suited for almost any environment including heat treat facilities, tool rooms, workshops, laboratories and inspection labs. Lifetime technical support is included on all Phase II Hardness Testers. So test away with confidence and a level of accuracy you will only find at Phase II.