Black Replacement USB Charger Cable 2 Pack by Bit Beat Sports, Compatible for Fitbit Flex Band Wireless Band Activity Bracelet. Black Fitbit flex USB cable, USB charging cable, compatible for charging the fitbit flex wireless band. Please Note: This item is only compatible with the Fitbit Flex and not other Fitbit products. It also does not have a reset function. Easy for charging, and convenient to carry. Replacement for lost or damaged cables Don't Worry About Battery Damage! - Has a PTC to ensure that your Fitbit Flex charger doesn't become damaged by overcurrent