Dwyer Series 490 Wet/Wet Handheld Digital Manometer, 0-50.00 psi Range Wet/wet digital manometer for balancing hydronic heating or cooling loops, evaluating pump or chiller performance, and determining pressure head loss from valves and pipe reduction Type 316L stainless steel wetted parts for use with compatible gases and liquids Accuracy is + or - 0.5% of full scale at 60 to 78 degrees F, and + or - 1.5% full scale at 32 to 60 and 78 to 104 degrees F Pressure measurement units include inH2O, mmH2O, bar, mbar, psi, inHg, mmHg, Pa, kPa Stores of up to 40 readings, and audible and visual alarms indicate out-of-range measurements