Utilize the extra space on your bike frame with the Outpost Frame Bag from Blackburn. This waterproof bag includes external mesh and slip pockets, as well as a main compartment with zipper for a secure place to store your belongings. The expandable bottom allows for additional room, while the straps attach to the bike frame to keep cargo weight centralized. . . . External mesh and slip pockets. . Main compartment with zipper. . Water resistant. . Expandable bottom. . Centralized cargo weight. . Includes hydration hose port. . Large holds 5.25L