UEi Test Instruments DTH31 Digital Psychrometer Triple Display 32 to 122F (0 to 50C) 0 to 100% RH -69 to 122F (-21.6 to 49.9C) Wet Bulb Range; -90.4 to 122F (-68 to 49.9C) Dew Point Range Min/Max/reset Data Hold Auto Power Off