A:Answer There are two USB ports that appear to share a 2.1 amp rated power supply circuit. I do not know what the recommended charge rating is for the Fitbit device you are asking about, but if it is significantly less than 2.1 amps (i.e. .8 ~ 1.2 amps) I would use the converter that accompanies the Fitbit rather than this device, as you may depreciate the life cycle of the battery in the Fitbit with the higher charging rate. If the Fitbit recommends up to 2 to 2.2 amps, this device will work fine for you.
