AIRLINE APPROVED: This carry-on backpack meets the size required by almost all major airlines and fits in the overhead compartment and under the seat. Of course the lie-flat opening design helps you get through security quickly. ADEQUATE STORAGE: The laptop backpack comes with 2pcs clothes storage bags and 1 shoe bag, different sizes can be used for different packing purposes, allowing you to store your clothes more conveniently and in an organized manner. UPGRADE ITERATION: Expandable design added for the first time, with 25L-40L of travel backpack storage space to change as you wish, the maximum capacity can store 3-5 days of clothes. TRAVEL DESIGNED: Comfortable airflow back design with thick and soft padding, effective back pressure relief, while equipped with adjustable chest buckle, so you hiking more easily. OCCASIONS: This travel backpack is perfect for weekend trips, business trips, hiking, camping, etc. Capacity：40L Weight: 2.26 pounds Material：Water-resistant polyester