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 & Smiley LCD display shows clear arrows, you can see temperature and humidity changes at any time. The backlight turns off automatically after 8 seconds without any setting. The smiley face symbol means - wet/comfortable/dry. Indoor temperature (0-50C / 32-122F) / Outdoor temperature (-50C-70C / -58F-158F), Humidity (20%-99%). Temperature and humidity accuracy is within 1C/5%. Temperature and humidity calibration and alarm function When the humidity and temperature reach the maximum or preset minimum, it sounds 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" key. 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 previous data and record again. The C/F button can toggle between Celsius and Fahrenheit. In addition, there are alarm settings for time (12/24-hour format), date, and upper and lower limits for temperature and humidity. USB powered The remote thermometer has two powers, battery (not included) and USB power, easy to use, you don't have to worry about battery replacement (including USB cable). The thermometer can be fixed through the hanging/socket hole. Very convenient to use. The three sensors have hanging holes on the back, which can be easily hung on the shelf.