Offering 11 selectable units of measure, the HD750 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's Data Hold and Auto Power Off functions. The 5psi HD750 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.