This practical charging accessory can hold and power three batteries in sequence. Take it with you to charge your remote controller, smartphone, or other devices when a top-up is needed.When used with a Usb charger, the Dji Mini 3/Mini 4 Pro Two-Way Charging Hub can charge up to three Intelligent Flight Batteries Plus in sequence from high to low power level. When used with the Dji 30W Usb-c Charger, the charging hub can fully charge one Intelligent Flight Battery Plus in approximately 78 minutes.When the charging hub is connected to Ac power through a Usb charger, users can connect both the Intelligent Flight Batteries and an external device (such as a remote controller or smart phone) to the hub to charge. The batteries will be charged before the external device by default. When the charging hub is not connected to Ac power, insert the Intelligent Flight Batteries into the hub and connect an external device to the Usb port to charge the device, using the Intelligent Flight Batteries as power banks. Refer to the Mini 3/Mini 4 Pro Two-Way Charging Hub User Guide for more details..