This water-resistant, wear-resistant rear-rack trunk bag is designed to give cyclists secure, versatile storage and fits most rear racks. It mounts with two fastener tapes for quick, stable installation, and can be carried off the bike using the top handle or detachable shoulder strap. The bag features a hard-case design, an elastic top band for extra items, dual-zipper access, and internal mesh pockets, plus a side water bottle holder with an adjustable drawstring. A reflective strip and taillight hanger help improve visibility.