This is the Team Associated SC28 USB Charger Cable.
Prevent transmitter battery drain with the 1:28 USB Charger Cable. This 27-inch cable allows you to charge the 1:28 battery from any power source with a USB outlet.
How the USB Charger works:
Once the USB charger is connected to a power source (i.e., computer or power block) and then plugged into chassis port, the LED will go red while it is charging. Once the process is completed the LED will turn green.