Please note: Please carefully confirm the type of purchase Fabric material: Canvas The trend of fashionable bag bags Shape: square type vertical section bags Open lid: zipper The internal structure: computer bags, mobile phone bags, bag Processing method: soft face Color: purple, blue, black, grey Besides being the safest backpack it is also the most convenient backpack with features such as: - Integrated USB charging port - Illuminating safety strips - Water repellent fabric - Weight balance - Luggage strap - Adjustable open angles - YKK zippers - Advanced storage design - Shock-proof Note: There is no mobile power comes with the backpack inside. If you want to use External USB Charge Function, you have to do as follows: 1.Buy a mobile power 2.Connect your mobile power with the USB interface inside the backpack 3.Connect your phone with the USB interface outside the backpack 4.Charging begins. There are 2 kinds of mobile power in the market. 1:Plug in your phone, you can start charging 2:Plug in your phone also need to press button of mobile power then start charging To cope with this backpack, we suggest purchase of the first mobile power.