Bontrager's Interchange City Trunk is a perfect combination of on-the-bike function and off-the-bike style. Pack its generous 803-cubic-inches with a change of clothes for your commute, books for class or just your daily necessities. Installing the City Trunk to your bike rack (sold separately) takes just seconds with Trek's Interchange system. At your destination the City Trunk removes just as easily and offers hand and shoulder straps for easy carrying. Other innovative design features include an internal stiffener to keep cargo in place and a unique base that protects the mounting hardware when not in use.