Topeak dynapack dxthis larger version of the topeak dynapack offers near trunkbag space without needing a rack and features an expandable top to hold a helmet shoes or other large objects molded from rigid eva foam and 420 denier nylon for a sleek aerodynamic shape a divided main compartment plus one zippered compartment handle organizational duties the lightweight aluminum exo frame features a quick release mount that attaches to seatposts measuring 245 34 9mm other features include a c