It features 11 selectable units of measure: in H2O,psi,bar,mbar,Kpa, ... ,mmHg,ozin2,FtH2O,cmH2O,kgcm,Additional features . 1.Product Name:Digital Manometer(1890)The device measures Gauge/Differential Pressure from -55H2O ... to +55H2O(+2 psi).It features 11 selectable units of measure: in H2O,psi,bar,mbar,Kpa ...