Topeak dynapack dx topeak dynapack dx gives you the carrying space of a rack pack but without fitting a pannier rack easily mounts using topeaks quickclickt seat post clamp molded from rigid eva foam the sleek aerodynamic shape provides a divided main compartment plus one zippered compartment to handle organizational duties and has an expandable top to fit bulkier items in size l x w x h 45 x 24 x 23 27cm weight 720g