Additel ADT761A [ADT761A-D-05-DP20-N] Low / Differential Automated Pressure Calibrator with CP35 and CP20 Sensors, 1/4NPT Female, 0.05%FS, 13.5 to 35 psig (-0.95 to 2.5 barg) and -20 to 20 inH2O (-50 to 50 mbar) is completely self-contained and automated with a built-in pump for pressure generation and precision control technology. With removable internal pressure modules, increased speed to pressure, ability to read two external pressure modules, touch screen display, Wi-Fi, Bluetooth, and Ethernet communications, double the original battery life, and more - simply set the desired pressure and watch the calibrator do the work. The Additel ADT761A-D-05-DP20-N provides differential and gauge measurement which covers the range of -13.5 to 35 psi (-0.95 to 2.5 bar). This unit comes with a CP35 module (-13.5 to 35 psi) and one low range module, DP20 -20 to 20 inH2O (-50 to 50 mbar). The ADT761A-D-05-DP20-N can be preconfigured with the modules that fit your needs, to give you the best precision at the pressures you perform calibrations.