Supports the following standards: ASTM D2435, ASTM D4546, ASTM D5333 For use in all Humboldt instrumentation. Switchable inch/metric digital indicators are accurate to ±0.0001 (0.002mm). Feature instant "0" at any spindle position, lock in maximum reading, LCD display with .305"-high characters, infrared linear encoder. Runs either clockwise or counter clockwise. Operates with replaceable batteries or AC power with automatic shutoff. Will replace any mechanical dial gauge. NOTE: HM-4471.10 is powered by a replaceable battery only.