Note: Tthis LED Dynamic backpack is small one,the size is about 26*11*30cm,it is more suitable for girls and ladies. 【DIY 】Modify the pattern at will, let the Crelander dynamic backpack as you wish. It has a sleek and cool design that's easy to spot in a crowd. Multipurpose:LED backpack has enough storage, which can effectively store cosmetics, tissues, keys, textbooks, mini ipad, cell phones, etc.... Comfortable: The Crelander Wireless Led Backpack's adjustable shoulder straps make the backpack comfortable to wear even when loaded with all your gear. The back panel, with a vented and well-padded design, also ensures comfort all the way. 【How to use】Search on your mobile phone or directly scan the code to download the APP, plug in the mobile power supply through the built-in USB data port on the back, turn on the BT and scan the QR code to bind the backpack. You can connect the device and use it. Please noted that for transportation safety, we do not provide mobile power.You have to prepare yours,the power supply :5V Crelander LED Display Backback(T7) Specification: Backpack Size:30*26*11cm Colors:Black / Pink/Purple/Blue Support Android and IOS systemsPower Supply of Power Bank(extra purchase) Ful Colors LED Screen 64*64 Resolution,Pixel Pitch P2.75 Screen Size 19.5CM*18.5CM Support Display: Text, Picture, Animation (GIF), Painting Usage:Daily, Travel, Outdoor Sport,Cycling, Business, Concerts, Parties, Business Activities, Advertising...etc.