Long Distance Transmission Wireless Thermometer Hygrometer with 3 Outdoor Sensors (433Mhz Frequency), you can place three sensors (waterproof Ip54) in different positions. Their data will be displayed on the same screen without frequent channel switching. The distance between the host and the sensor: The transmission distance is 300 feet / 91 M long (without obstacles or walls), and the effective transmission distance is up to 100 feet / 30 M (with obstacles). White Backlight and Smiley Display The LCD screen shows clear arrows, you can see the temperature and humidity changes at any time. The backlight will automatically turn off after 8 seconds without any setting. The smiley symbol means - Wet/Comfortable/Dry. Indoor Temperature (0-50C / 32-122F) / Outdoor Temperature (-50C-70C / -58F-158F), Humidity (20%-99%). Temperature and humidity accuracies are within 1C/5%. Temperature and humidity calibration and alarm function When the humidity and temperature reach the maximum or preset minimum, it will sound and the backlight color alarm (the backlight changes to red and orange). If the temperature and humidity are outside the normal error range, you can manually correct the error by pressing the \"Time-Set\" button. 5 Buttons Our hygrometer thermometer can record temperature and humidity over time, the Min/Max button can display all temperature and humidity Maximum/Small value data, long press can delete the previous data and re-record. The C/F button can switch between Celsius and Fahrenheit. In addition, there are alarm settings for time (12/24-hour format), date and upper and lower limits of temperature and humidity. USB Powered The remote thermometer has two power supply methods, battery (not included) and USB cable power supply, easy to use, no need to worry about battery replacement (including USB cable). The thermometer can be fixed through the hanging/base hole. Very convenient to use. The three sensors have hanging holes on the back, which can be easily hung on the shelf.