Specifications: It is used to measure indoor and outdoor temperature and humidity. The thermometer hygrometer has the highest and lowest temperature and humidity memory function and it can view historical temperature and humidity data. It can be connected to 3 outdoor units at most. There is a bracket on the back of the host, which can stand in a horizontal position. With backlight, it will automatically turn off the backlight after 10 seconds without operation. The XP4 waterproof outdoor unit can be hung with hanging holes or stand on a horizontal surface. Item Name: Thermometer Hygrometer Material: Plastic, Electronic Component Indoor Temperature Range: -4 Fahrenheit Degree-158 Fahrenheit Degree (-20 Degree Celsius-70 Degree Celsius) Outdoor Temperature Range: -40 Fahrenheit Degree-158 Fahrenheit Degree (-40 Degree Celsius-70 Degree Celsius) Humidity Range: 20%-95% Comfort Display: Dry, Comfortable, Wet Temperature Display Unit: Degree Celsius/Fahrenheit Degree Optional (Default is Degree Celsius) Temperature Resolution: 0.1 Degree Celsius/Fahrenheit Degree Humidity Resolution: 1% Refresh Rate: 10 Seconds Error: Temperature Plus or Minus 1 Degree Celsius, Humidity Plus or Minus 5% Wireless Receiving Range: 60m/197Inch RF Wireless Frequency: 433MHz Power Supply: 2 AAA Batteries (Not Included) Features: Large Screen, LCD Display, Accurate, High Sensitivity, Easy to Operate, Thermometer Hygrometer Tool Host Size: 95mm x 24mm x 112mm/3.74" x 0.94" x 4.41" (Approx.) Transmitter Size: 100mm x 35mm x 20mm/3.94" x 1.38" x 0.79" (Approx.) Notes: Due to the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x User Manual 1 Set of Thermometer Hygrometer (Batteries Not Included)