For Tello Drone Flight Batteries, Works with GB1 1100mAh/3.8V Batteries, Charges up to 3 Batteries in Sequence, 5V/3A Maximum Input Power, Requires a USB Charger (Not Included). Make sure all of your Tello batteries are charged up with this Tello 3-Bay Battery Charging Hub from Ryze. This hub can accommodate up to three batteries saving you the time and energy of charging each battery individually. The hub charges your batteries in sequence according to their voltage levels from highest to lowest. That means that the battery with the highest voltage is charged first and when it's completely charged the battery with the second highest voltage will automatically begin charging and so on. Please Note: This hub does not include a Micro-USB cable and USB charger but one is required in order to power this charging hub. This hub supports a maximum of 5V/3A of input power. When tested using a CE-certified USB charger with a rating of 5V/2A the hub fully charged all three batteries in approximately two hours.