Canvas Usb School Bags for Girls Teenagers Backpack Women Bookbags Black 2023 Large Capacity Middle High College Teen SchoolbagThe USB interface of this bag is just a transfer interface from the inside to the outside on the bag; The factory does not have a charging device (power bank). There is a USB link line inside the bag for the connection between the battery and the internal interface, and the external mobile phone charging line interface is linked with the external interface, forming the principle of internal and external connection charging. Comfortable: Adjustable S