The arctic hayes digital differential pressure meter is ideal for domestic tightness testing has a digital back lit display that can show gauge or differential pressure in 11 different pressure units mbar psi inches h2o bar kpa in hg mm hg ozin ft h2o and kgcm other features include a record function for holding measurements maxmin pressure feature auto power off and a low battery indicator specification pressure ranges 0 138mbar 0 554 inches h20 0 1410mm h20 0 2psi 0 0138bar