Description: -The device is based on the technology of electronic bearing sensor and barometric sensor. 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 in any time.  -8 in 1 Function: Digital altimeter, with digital barometer, digital compass, weather forecast, time, calendar, thermometer, and backlight -The device is based on the technology of electronic bearing sensor and barometric sensor.  -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 in any time.  -Forecast the weather for the forthcoming 12 to 24 hours basing on barometric pressure changes.     Specification : Waterproof Level:IPX4;  Clock Format:12/ 24;  Calendar:Perpetual Calendar;  Display:LED Backlight;  Height Range:-500~8000 m;  Compass Range:0° to 359°, 1-16 Pointer (Graphic);  Relative Height Measurement Accuracy:±3.0 m;  Absolute Height Measurement Accuracy:±12 m;  Angle Measurement Accuracy: ± 8°;  Temperature Measurement Range:-20 to + 60°C (-4 to +140°F);  Temperature Accuracy:+/- 1.0 °C;  Measurement Temperature Interval: 60 sec In Normal Weather / 3 sec Altitude Measurement;  Air Pressure Resolution:0.1 hPa (0.1 mmhg, 0.01 inHg);  Pneumatic Accuracy:+/- 1.5hPa;  Power Supply: 3V Lithium Battery (CR2032) Included;  Battery Life:6-12 months;  Size:5 x 9 cm;     Package Includes: 1 x Digital Compass;  1 x CR2032 Battery;  1 x English Manual