This versatile bike rear rack bag is the perfect companion for cyclists who demand both functionality and durability. With an impressive 10L (2.64 gallon) capacity, this spacious bag provides ample room for all your cycling essentials, tools, snacks, and personal items. Measuring 15.7 inches long, 7.9 inches high, and 2.8 inches wide, it offers generous storage without compromising your bike's balance. The bag features a hard PU construction that maintains its shape while protecting your belongings from impacts and rough terrain. Built to withstand the elements, this fully waterproof bag utilizes PU and EVE waterproof fiber material combined with a waterproof zipper to keep your gear dry even in heavy rain. The thoughtfully designed water bottle bag provides easy access to hydration during your ride, while the integrated tail light buckle enhances your visibility and safety on the road. Reflective elements and tail reflection strips ensure you're seen by motorists in low-light conditions. Secure attachment is guaranteed through multiple velcro straps and buckles, along with elastic rope for additional stability. The bag stays firmly in place even on bumpy trails or during aggressive riding. Whether you're commuting to work, touring long distances, or hitting mountain trails, this bike rack bag delivers the storage capacity and weather protection serious cyclists need.