JB Industries DV-40 Supernova Digital Micron Gauge Factory calibrated and requires no additional calibration - Measures in MICRONS, PSIA, INHG, PASCALS, TORR, MTORR and MBAR If sensor gets contaminated, clean with simple alcohol - Programmable alarm allows you to perform other tasks Duration of backlight is programmable - Brass fitting on lengthy flexible cord for hard to reach places Programmable shut-off - Large, easy to read LCD screen The female connection on this unit allows for direct connection to the A/C unit without need of hose connection