The Acu-Rite VUE 200S 532883-02 Digital Readout (DRO) is for 2-axis milling, turning, and grinding.

The most popular digital readout system in the machine tool marketplace, the 200S
incorporates LCD display technology with versatile software to accommodate milling,
turning and grinding applications. Designed and manufactured in the USA, ACU-RITE digital readouts are the first choice of machine tool builders and users alike.

Here is the product manual (PDF).