The HD750 Differential Pressure Manometer, with 11 selectable units of measurement, can function as a short range/high resolution Gauge or offer Differential Pressure ranging from 0 to 138.3 in. H2O (inches of water). The Max/Min recording and Relative time stamp functionalities, as well as the HD750’s Data Hold and Auto Power Off functions, are useful. The 5psi HD750 also has a Zero function for offset correction or measurement, as well as an integrated USB port. It includes a 9V battery, software with a USB cable, an AC adaptor, a connection hose, a built-in stand, and a protective carrying case.