Topeak mtx trunk bag dxp this is the largest topeak mtx trunkbag featuring a new process that marries rigid molded panels with flexible 600 denier fabric to make these the stiffest most weather resistant mtx bags yet the divided main compartment features a two stage expanding top plus side panels that zip open into full panniers for even more capacity compatible with all mtx quicktrack racks with attached side frames mtx side frame are required for use on mtx trunkbag with panniers features