Digital Display Ruler Horizontal Readout Scale Industrial Assembly Measuring Tool 0‑500mm Item Type: Digital Display Ruler Material: Plastic + aluminum alloy Range: Approx. 0-500mm / 0-19.7in Accuracy: 0.01 Battery Model: CR2032 (not included) Type: Fixed Other Function: Remote data transmission (transmission port attached to the sensor) Application: Suitable for lathes, milling machines, router tables, planers, table saw fences and other machine tools. Use it to equip and upgrade old lathes and various industrial lathes. How e: Load the battery or chain to connect the power supply e, turn on the power, press the ZERO button to reset to zero, and the mm/in button to change the display unit.