Tbags Expandable Roll Bag - Converts from a 1-cu.-ft. day bag to a 2-cu.-ft. highcapacity touring bag. Expandable mounting system adjusts to fit all backrests 7in. to 14in. Built-in bungee-bottom external rain cover for all-weather protection. Organizer pocket for phone, pens, keys and maps. Constructed from 1680-denier ballistic nylon with fade-resistant UV treatment. Vertical support and stability from dual-wall construction filled with 6-lb. high-density foam. Equipped with eight nylon bungee attachment loops for added cargo tiedown. Four large external side pockets. Great solo backrest. Padded backpack straps stow away in their own zippered compartment. Semirigid luggage design stores flat. Available with or without soft top roll bag, which has its own mounting system and can be used separately. Always set on luggage rack or passenger seat pad. Expanded dimensions: 14in.W x 20in.H x 10in.D (2 cu. ft.) . Unexpanded dimensions: 14in.W x 20in.H x 5in.D (1 cu. ft.) . Roll bag dimensions: 14in.W x 10in.D (.5 cu. ft.) .