Barometer: The current barometric pressure is displayed on the screen immediately after power-on. Press the [ALTI/+] button to switch between barometer and altimeter. Altimeter: The altitude value displayed on the screen after power-on is the sea level altitude of the current location. In altimeter mode, press the [SET] and [ALTITUDE/+] buttons simultaneously, you can press [+] or [-] to change the current altitude value. Relative altimeter: The use of the relative altimeter is to reset the altitude value measured at this time, and use the position at this time as the 0M altitude point, and the altitude value that rises or falls from the 0 altitude point is the relative altitude value. To reset the altitude value, press and hold the [ALTI/+] button until 0M is displayed at the bottom of the screen, and then start moving, and the relative altitude value of the movement will be displayed on the screen. Press and hold the [ALTI/+] button again to switch back to the actual altitude value. Weather forecast: It can predict the weather conditions within 12 to 24 hours when it is powered on, and the effective range is 30-50 km. 1. Long press the [SET] button for 2 seconds, 24Hr flashes, press the [ALTI/+] button to switch between 24Hr or 12Hr. 2. Press the [SET] button to enter the time setting, at this time the hour digits flash, press [ALTI/+] or [-] to set the hour value. 3. Press the [SET] button to flash the minutes, press [ALTI/+] or [-] to set the minutes. 4. Press the [SET] button to flash the calendar year number, press the [ALTI/+] or [-] button to set the year value. 5. Press the [SET] button to flash the calendar month number, press the [ALTI/+] or [-] button to set the month value. 6. Press the [SET] button to flash the calendar date number, press the [ALTI/+] or [-] button to set the date value. 7. Press the [SET] button to flash the temperature unit Celsius, press the [ALTI/+] button to switch between Celsius or Fahrenheit. 8. Press the [SET] button and the pressure unit HPA flashes, press the [ALTI/+] button to switch to the pressure unit HPA/inHg/mmHg. 9. Press the [SET] button to flash the altitude unit M, press the [ALTI/+] button to switch between the altitude unit M or FEET. 10. When the setting is complete, press [HISTORY] to exit the setting mode, or automatically exit the setting without any operation within 10 seconds. Color: Black gray Material: ABS Size: 9 x 5 x 2cm Package contents: 1 x altimeter barometer 1 x English manual 1 x CR2032 button battery (not included) Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3 cm.