Larger capacity: 10-25L Expandable capacity, folded size: 32*17*19cm, extensive side pocket (35*28cm), 1 main compartment, 2 side pockets and 1 water bottle pocket on the back. The side pocket and top pocket are expandable, provide extra storage space to store whatever you want. such as bike pump, tools, patch kit, spare tubes, lock, chain, a change of clothes, groceries and a few other necessities. Waterproof Material --- Made of high quality 600D oxford fabric: solid, smooth , waterproof, durable, anti-scratch, etc. The rainproof cover (included) provides further protection for the things inside. Easy Installation: There are 2 nylon buckles at the bottom of the bag to attach the bag to the Bicycle rear seat can be attached. There is an elastic cord at the top of the trunk, which can be used to easily put in or take out your stuffs, such as rain jacket, gloves, umbrella, repair items, tripod, etc. Multipurpose Features: With an adjustable padded shoulder strap ( 70-130 cm), this bike backpack not only can be fixed on the back seat of the bike, but also serves as a handbag and shoulder bag after the bike is parked. Perfect for outdoor hikes, picnics with friends or weekend trips or commuting to work or school. A wonderful gift for a dear friend or loved one. Triple safety protection: Reflective straps on both side pockets ensure your safety in the dark. The taillight hanger allows you to hang a taillight on your back for better visibility at night or in low-light situations. The bonus rain cover also helps others. Find out quickly when riding in rainy or damp conditions. Reflective strips on both side pockets ensure your safety in the dark or low light conditions. Comes with a shoulder strap for your outdoor hikes, picnics, or commute. The design with four Velcro straps makes it easy to mount this bag on your bike rack. Two dividers inside the bag help you divide the inside of the bag as you need. With the extra waterproof rain cover, the bag can be dried in rain or wet weather.