Durable Fabric：Outer: High quality nylon composite waterproof fabric (Abrasion-resistant). Internal: Polyester Smart LED Backpack: Unleash your creativity with LED Space app. We have updated the APP to V2.0.0 version in May and improved many functions!! It is more easier to use.The backpacks can display texts images animations doodle How to use: LED screen is powered by external power bank (Not included). Connect your power bank with the internal USB charging port. Connect the WI-FI and use app for iOS and Android Design: Adjustable shoulder straps with mesh fabric for superior back ventilation and support.  Exterior Dimension Space: 17.3 X 13.5 X 5 inches. The backpack can fit up to a 15.6" laptop