The device is based on the technology of electronic bearing sensor and barometric sensor 8 in 1 Function: Digital altimeter, with digital barometer, digital compass, weather forecast, time , calendar, thermometer , and backlight. The digital altimeter is designed for outdoor use, the detachable string makes the digital compass a perfect hand-carry device for various outdoor activates it will give you backlight when you press any button Digital thermometers are portable instruments for measurement of temperature, have permanent or removable probes , with a digital display and are typically battery powered. Digital thermometers can have many display scale characteristics. These include Fahrenheit display, display range and scale divisions, Celsius or Centigrade display, display range and scale divisions. Digital thermometers can display temperature in Fahrenheit or Celsius, or both in a dual scale thermometer. The display range is the minimum and maximum values of temperature that can be displayed. The scale division is the smallest division of degrees that can be displayed. Scale division may also be referred to as resolution in digital instruments.