TFA digital thermo hygrometer for indoor and outdoor temperature. Maximum and minimum function. Wall mounting or table standing. 1.5 volts AAA battery included. Temperature range: indoor 0 to +50 degree C (+32 to +122 degree F), outdoor -40 to +70 degree C (-40 to +158 degree F), Humidity indoor 20 to 99 percent. Measures 91 mm width by 134 mm height by 18 mm depth.