Customize the message you want. Ideal for Trade Shows, Events, Parties, etc. Features:  Waterproof Material: Using water-repellent film to protect your LED screen. Can work even in rain.  Easy to Use: 3 steps: Plug in the power bank --〉Pair the Backpack to your smartphone device by WiFi connection--〉Use the APP to control displayed images, animations or text right on your Backpack.  Soft: Sshaped adjustable shoulder strap, shoulder strap designed and padded shoulder strap can effectively share weight and travel easily. Ergonomic backpack and back wrapping designed can effectively relieve shoulder pressure and travel easily.  Widely Used: It is a programmable sign for portable billboards, advertisements, holiday wishes, slogans, and business promotions.