The Triplett DPR302-NIST Differential Pressure Manometer measures gauge and differential pressure to ±2psi and comes with Certificate of traceability to NIST standards . Use one input to measure the gauge pressure of a single source. Use both inputs to measure the differential pressure between two points of a single source or between 2 sources revealing which input has the higher pressure and the difference between them. Measurements are viewed on the large backlit LCD display in 11 units of measure. Min/Max/AVG records highest, lowest and average readings with relative time stamp. Data Hold momentarily freezes the displayed reading for easy viewing. The Triplett DPR302-NIST features convenient quick‐disconnect fittings, zero adjust, offset function, and auto power off with disable.