LOVEVOOK Travel Backpack, 30-40L Expandable Extra Large Backpack with Lock, Carry on Backpack 17 Inch with USB Port, Anti-Theft Water Resistant Business Backpack for Men Women, Dark Grey

[30-40L EXPANDABLE CAPACITY]: This large travel backpack with an expandable design. Before extended is 30L, dimensions are 13*6.5*20inch; after extended is 40L, dimensions are 13*9*20inch. Fits most 17.3/17/15.6/inch laptops. The carry-on backpack meets the maximum size allowed by IATA flights.
[ANTI-THEFT DESIGN]: The two lock heads can be locked in the middle to protect your belongings from theft. Extra large backpack back zipper pocket protects your precious articles, such as phone, passport, wallet. The black backpack for airplanes is a good choice for business/travel.3 custom-made storage bags.
[WATERPROOF DESIGN]: The expandable business travel backpacks are made up of durable abrasion, scratch, and water-resistant materials, which can provide protection on drizzle days. Internal waterproof pouch in our carry-on backpack to protect your goods from water.
[CONVENIENT FUNCTION]: The two handles of the carry-on backpack are set on top and one side, easy to be carried vertically or horizontally. The USB port is on the side of the weekender backpack. The luggage belt on the back of the large laptop backpack allows being slid over the luggage tube.
[COMFY FUNCTION]: Ergonomic airflow back design with thick but soft ventilated padding. Breathable and adjustable shoulder straps relieve the stress of shoulder. Shoulder straps with an adjustable anti-slip chest belt and quick-release. Foam padded top handle for a long time carry on.