To charge the Duo, first rotate or flip the case, if necessary, so that the dial face is showing; do not press the case back into the cradle yet. This will expose two contacts on the lower edge of the case.
Next, hold the two metal pins on the charger against the contacts on the case, and press the two arms of the charger onto the case as shown in the lower photograph (the charger included with the square Duo has only one arm).
Next, make sure that the USB cable is fully plugged into the charger, and plug the other end of the USB cable into a USB port on your computer. It will take approximately 2–3 hours for the Duo to charge completely.
To check the battery level while the Duo is charging, look at the LCD display and press any of the three buttons. When the Duo is fully charged, the LCD display will display a battery level of 100% until the charger is unplugged.
If your Duo is not charging, be sure that the pins are fully seated in the contacts on the watch. Make sure the USB cable is fully seated into the charger.
Note: To charge the Duo more quickly, plug the charger into a USB wall adapter (not included) or a USB car charger (not included).
To remove the charger from the Duo, first lift the arm(s) of the charger off the case.