EXPANDABLE TRAVEL BACKPACK Large capacity with an expandable design to fully meet your storage needs. The interior features a multifunctional, compartmentalized layout with wet and dry zones, plus pockets designed to neatly hold tablets, cell phones, and books. VACUUM COMPRESSION SYSTEM Dual shoulder bag compression with an exhaust valve to expel air and create extra storage space. You can manually remove air if desired. An electronic vacuum pump is included to minimize space waste; the pump can be used for inflation and deflation, and a set of nozzles is provided to fit various scenarios. WATERPROOF DESIGN Multilayer waterproof construction. The outer layer is made from waterproof Oxford fabric, and the inner vacuum sealing bag is TPU fabric. Even if the backpack is submerged, the contents stay dry. ANTITHEFT LOCK Customs combination lock design that can be unlocked with a special customs key after inspection. The lock can also be set up with a password for easy, independent security. USE SCENARIOS International or long trips: expandable capacity to accommodate clothes and gear; vacuum compression reduces bulk for efficient packing; waterproof materials protect contents from moisture; antitheft lock adds security during transit and at accommodations. Business travel and daily commuting: dedicated pockets for tablets, cell phones, and documents; organized storage for quick access and neat presentation. Outdoor activities or gym visits: wet and dry zones keep damp items separated from dry ones; compact packing when on the move. MATERIALS AND PERFORMANCE Outer material: waterproof Oxford fabric. Inner sealing bag: TPU fabric. Features include expandable capacity, vacuum exhaust valve, electronic pump with multiple nozzles, and an antitheft customs lock with password options.