Features 1.The S-shaped shoulder strap is ergonomic to protect your shoulders and spine. 2.Pencil pocket,many zipper pockets,and a key hanger inside, which are fully functional. 3.A special pocket for storing powerbank inside, which will not be disconnected during bumps. 4.Waterproof resistant, scratch resistant, water repellent, but please don't let the backpack "bathe" in heavy rain. Bag's size and fit guide 15.6 inch bookbag is ideal for people of height from 4.5ft to 6.25ft. 17.3 inch bookbag is ideal for people of height from 5.3ft to 6.4ft. Suitable for a variety of Occasion College Backpack,high school backpack,middle school backpack Business backpack,computer backpack,laptop backpack,office backpack,travel backpack Specifications Size:18 X 13 X 8 inch(15.6inch)/19 X 14 X 8 inch(17.3inch) Capacity:35L-40L Weight:1.8lbs Gender:Unisex Closure Type:Metal Zipper Material:Waterproof Polyester Style:Laptop/School/Business/Travel Laptop Compartment:13inch,14inch,15inch,15.6inch,16inch,17.3inch Package Include Backpack x 1 Usb cable x 1