Used see photos. Tested working under vacuum. It is accurate, but not calibrated.
About this gauge, "MKS / HPS Granville-Phillips 909AR miniature ionization gauge transducer for high-vacuum and UHV pressure measurement in vacuum chambers, thin-film deposition systems, sputtering tools, evaporators, ion pumps, turbo pump systems, leak-check setups, semiconductor process tools, research vacuum lines, analytical instruments, and lab vacuum service. The 909AR is a hot-cathode Bayard-Alpert style transducer with integrated electronics, analog output, digital communication, and relay setpoint capability. Product page describes the 909AR as supporting RS232 or RS485 communication, 0-10V semilog analog output, and use with the PDR900 controller; the KF25 variant is listed as 909AR-41 for RS-232 or 909AR-42 for RS-485"
