Larger capacity: 10-25L expandable capacity, folded size: 32*17*19cm, wide side pocket (35*28cm), 1 main compartment, 2 side pockets and 1 water bottle pocket. Expandable side and top pockets provide extra storage for anything you want. Things like bike pumps, tools, patch kits, spare tubes, locks, chains, a change of clothes, groceries, and a few other essentials. Waterproof Material---Made of high quality 600D Oxford cloth: strong, smooth, waterproof, durable, scratch resistant, etc. A rain cover (included) provides further protection for the contents inside. Easy to install: There are 2 Velcro tabs on the bottom of the bag, which can be used to secure the bag to the back seat of the bike. There is a rubber cord on the top of the trunk, which makes it easy to put in or take out your belongings such as raincoats, gloves, umbrellas, maintenance supplies, tripods, etc. Multipurpose Gear: With adjustable padded shoulder straps (70-130cm), this bike backpack can not only be attached to the back seat of the bike, but can also be used as a tote and shoulder bag when the bike is parked. Perfect for outdoor hikes, picnics with friends or weekend trips or commuting to work or school. A great gift for a dear friend or beloved family member. Triple Safety Protection: Reflective tapes on both side pockets keep you safe in the dark. A taillight hanger lets you hang your taillights on the back for better visibility at night or in low-light situations. The extra rain cover also helps others find you quickly when riding in rainy or wet conditions.