JB's DV-22 reads vacuum in seven international units: microns, PSIA, InHg, mBars, Pascals, Torr, and mTorr. The DV-22 has a micron range of 20 to 9,000 microns. It is a good idea to attach the micron gauge to the vacuum pump before evacuation to make sure the pump pulls down to at least 50 microns. If it doesn't, your pump oil is contaminated and should be changed. A compound gauge only indicates that a vacuum is being produced, but does not tell you if moisture and acids are still present in the system. Micron gauges are the only tool to accurately read the low pressure produced when evacuation/dehydration is complete.
JB Industries Vacuum Gauge, 10 to 100000 um Measuring, Alkaline Battery, Backlit Display, 32 to 120 deg F, 9 in L x 3-1/4 in W x 1-1/2 in D, Additional Information: AA Battery Size
Specification Sheet- DV-22N digital vacuum gauge is an easy-to-use, compact vacuum gauge featuring a sleek new design with enhanced user settings and an extended range sensor
- Extended range MEMS sensor
- Easy-to-read backlit display
- Intuitive user menu with custom setting options
- Allows for direct connection to the A/C unit without a hose
- Audible and visual alarms when target vacuum level is achieved
- Low battery indicator with automatic shut-off
- Measures in ums, psia, in hg, Pascals, torr, mtorr and mbar