Extech 407910 Heavy Duty Differential Pressure Manometer (29psi)Extech 407910 Heavy Duty Differential Pressure Manometer Heavy Duty Differential Pressure Manometer Wide range dual input With multiple units and RS 232 interface Key Features: Dual differential inputs with internal sensors Wide (802 inches of water) measurement range with high resolution Displays 8 types of pressure units: mbar, psi, kg cm2, mmHg, inHg, mH2O, inH2O, and atm Record Recall MIN and MAX readings Data Hold and Auto Power off Zero function