Colour Name:WhiteColour Name:BlackS1 key: short press backlight, long press lock screen&lock keyS2 key: Up/Down/OK, long press enter settingsS3 key: Exit/ReturnS4 key: switch below area & value settings + 11. Time display function, display time, minute, second, month, day,week, 12/24H, initial value is（2020-1-01 12:00 00 WED ）2. Alarm function3. Countdown function, the initial value of (0:00.00,12:00(0FF)4. Stopwatch function, the initial value is (0:00’000, (0FF)5. Step counting, exercise time, pace, mileage, calories consumption6. Altitude, relative altitude7. Air pressure curve, air pressure, air pressure curve view (24H)8. Exercise time record, movement relative height view.9. Diving function, one is scuba diving, one is free diving. Scuba divingwith NDL time,depth,Temperature,diving speed.10. Diving log (99 records)11. Compass calibration function12. Low-power reminder13. Backlight function14. 4 key functions15. Use the Battery CR2450This product can not replace the formal diving education and training. This product is intended for use only by divers who are trained by a certified professional diver and know how to operate diving equipment.