Uniweld UVG3 SmarTech® Digital Vacuum Gauge provides unsurpassed vacuum accuracy and quickly measures vacuum in Measures in Microns, Pascals, Millibar, mmHg, mTorr with a resolution down to 0.1 micron. Oil Filter Disk Prevents Sensor Contamination. Keeps your sensor clean and accurate! Temperature Compensated Self-Calibration. Large, High-Visibility Backlit LCD Display. Requires (1) CR123A Battery (included).