This larger version of our 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 600 denier polyester 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 24.5, 34.9mm. Other features include a convenient carrying handle and 3M reflective strip and RedLite clip for extra safety.