The Airserco 8990-SM analog high vacuum gauge displays vacuum level from 0 microns to atmospheric pressure, with 100 micron gradients from 0-2000 microns. It is anaffected by changes to ambient temperature, is highly responsive, and operates on 115 volt, 60hz, single-phase power. 230 volt available upon request. The 8990-SM utilizes the 8970-SM gauge tube pressure transducer. One gauge tube is included with each vacuum gauge purchased.