Offering 11 selectable units of measure, the HD750-NIST Differential Pressure Manometer can serve as a low range/high resolution Gauge or provide Differential Pressure up to 0 to 138.3 in. H2O (inches of water). Max/Min recording and Relative time stamp are useful features, as are HD750-NIST's Data Hold and Auto Power Off functions. The 5psi HD750-NIST also features Zero function for offset correction or measurement and a built-in USB interface. Comes complete with 9V battery, software with USB cable, AC Adaptor, connection hose, built-in stand, and hard carrying case. Includes certificate traceable to NIST.