[ EXPANDABLE DESIGN ]: Dimensions: 17.7 x 12.6 x 7.1 - 10.1 inches. Expandable backpack has smooth zippers on the side of the main compartment. Once pull on the zipper, the bag will offer a large capacity up to 38 L for you to store more stuff [ UPGRADE USB-C ]: FENRUIEN smart backpack gives you a provision to connect your power bank and gives you access to it via USB port outside on the backpack (Power bank is not included) [ TSA FRIENDLY ]: It can be opened 180 degrees for airport checkpoint. When you pick up your check-in luggage, sling this travel backpack over the handle using the built-in back strap to keep your hands free throughout the airport [ LONG-LASTING MATERIAL]: Slim backpack is made of 900D water resistant PU coated oxford fabric and smooth YKK zippers (Zippers are not waterproof), which gives your electronic and precious items provide adequate protection [ COMFORT & CONVENIENCE ]: The ergonomic straps and breathable mesh backing help to ease pressure on yo