This 4 in 1 digital thermometer psychrometer is designed to combine the functions of humidity meter, temperature meter, wet bulb temperature and dew point temperature. With backlight, LCD display, low battery indicator, automatic shutdown, max and min functions. Switchable °F/°C temperature. Suitable for warehouse, outdoor, freezer, lab, greenhouse, refrigerated truck, and etc. Ambient temperature range: -20℃~60℃ (-4℉~140℉); ambient temperature accuracy: 0℃~45℃±1℃ (other: ±1.5℃); humidity range: 0.0%~99.9%RH; humidity accuracy: 20%~80%±3.0%RH (other: ±4.0%RH); wet bulb temperature range: -20℃~60℃ (-4℉~140℉); wet bulb temperature accuracy: 0℃~45℃±1℃ (other: ±1.5℃); dew point temperature range: -50℃~60℃(-58℉~140℉); dew point temperature accuracy: 0℃~45℃±1℃ (other: ±1.5℃).