🚴17L CAPACITY: Our bike rack bag includes a 9.5L main compartment, 2 added side bags, 5 inner mesh pockets, an extra top pocket, and an adjustable elastic cord. Dimension of 15.35 x 10.25 x 7.87 inches(L x W x H), it's up to 17L, large enough to store and keep riding essentials organized, such as bike tool kit, pump, wallets, phones, power banks, small speakers, towels, clothes, food, drinks, bike locks, sunglasses, etc. 🚴WATERPROOF HARD SHELL DESIGN: The bike trunk bag is made of EVA, coated with PU. It features water resistant, sturdy, lightweight, and easy to clean. Solid shapes make it not deform and look stylish. The bike bag also comes with a rain cover, so no worry about cycling on a rainy day. 🚴REFLECTIVE: The reflective design on four sides increases nighttime visibility, and the taillights (not included) are hung on the rear strap making your cycling safer. 🚴EASY TO INSTALL: With 4 velcro straps, the bike pannier is installed and unloaded in seconds, ensuring its max stability and security. Adjustable straps make it fit on most bicycle racks, like mountain bikes, road bikes, e-bikes, hybrid bikes, and gravel bikes. 🚴YOUR GREAT BIKING BUDDY: With the shoulder strap and the handle, the bicycle bag is easy to carry. No matter what kind of occasion, such as picnics, camping, commuting, hiking, or travel, it will be your good partner.