Park Tool BX-3 Rolling Big Blue BoxPark Tool BX 3 Rolling Big Blue Box. Built to withstand the punishment of travel and constant use and molded from impact resistant polypropylene the BX 3 features pallets with 70% more surface area than the BX 2. 2. Easily transportable with the integrated wheels and extendable handle this case was designed with the help of some of the worlds best mechanics for optimal form function and longevity. Smooth rolling integrated wheels Extendable handle