UEi Test Instruments EM201B Test Dual Input Differential Manometer Dual input measures up to 40 Inch of water gauge. NOTE .001wg resolution below 9.999 Inch. Ruggedized with sturdy metal fittings Scales include Added Pascal's as a measurement scale, Wag, mbar and PSI. Dynamic Min/Max that can be reset at any time Data hold, Auto power-off and Back-lit display Three year limited warranty