Each anvil can be used for both metric and unified external threads. The correct pair of anvils must be selected and inserted in the hollow micrometer spindle and anvil. The micrometer anvil is fully adjustable by the knurled knob located on the anvil side of the frame. Zero set the micrometer with this knob whenever the anvil is interchanged. The 326 Series provides digital readout to .00005" (0.0001mm) and can be linked to the SPC system. Functions: Origin setting. Data Hold. Inch/Metric Conversion. SPC output. Low battery voltage alarm. Scale contamination alarm.