Vacuum Measuring Range High Pressure Pirani Range 1000mBar to 0.001mBar (1 Micron) or 1 mBar to 0.001 mBar ( 1 Micron ).    Principle :  Based on thermal conductivity of gauge to Measure Negative Pressure (Vacuum) gauge head single pirani gauge head with KF clamp optional dual ( Double ) gauge head to measure at 2 places with one instrument, push button on front panel to toggle with LED indication of selected gauge head.      Accuracy : +/- 1 % of Reading  Display : 3 Digit 0.5” High Red LED  Power : 230 V.A.C., 50 Hz  Size : 96 x 96 x200 mm. ( LxBxD)