polyester lining Zipper closure Size of Boys Rolling Backpack: 11.8"x 9"x 18.11"(L*W*H); about weight: 2kg; the rolling backpack with durable rubber solid 6 wheels design, sliding fast, not stuck, wear-resistant, the wheels are perfect for going up steps and curbs Material of Rolling Backpack: Anti-splash water nylon fabric, lining is polyester, durable, anti-scratch, and water-resistant, better protect the items in the kids backpack from getting wet, and easy to wipe down. This boys rolling backpack with sturdy zippers, triangle sewing reinforcement, adjustable padded straps and durable wheels and handles, can last the entire academic year Rolling Backpack with Multi-Pocket: Boys rolling backpack with multiple pockets, 1 large capacity main pocket with compartment, 3 front zip pockets and 2 side pockets, easy to hold all for school supplies, such as tablet, books, homework folders, iPad, folded umbrella, water bottle, ect. Detachable 6-Wheel Trolley: After correct assembly, the backpack can stay on the trolley stably without rollover, wear-resistant rubber wheels, reinforced aluminum alloy double handle, telescopic design can save space. you could use the backpack with the trolley or trolley can be separated use if desired Occasion of Trolley Bag: This rolling backpack perfect for school, travel, work; it is suitable for primary middle high school kids and adults. Please contact us if you have any questions or dissatisfied, we will refund or replacement to ensure you a