Mavic Open Pro Shimano Ultegra 6800 Road Wheelset. A classic in every sense of the word, Mavic Open Pro rims laced to Shimano Ultegra 6800 hubs are the ultimate in reliability, serviceability, and performance in all conditions out on the road. The Open Pro rims are constructed of Mavic's proprietary Maxtal aluminum alloy which creates a rim that's both stronger and lighter than 6106 alloy. For added performance advantage, the rim features a welded joint for strength plus a CNC machined braking surface to enhance stopping power. You can't go wrong with Shimano Ultegra 6800 hubs that feature silky smooth sealed cup and cone bearings. The rear wheel's cassette body is set up for Shimano or SRAM 891011 speed systems, so it will serve you well on a variety of drivetrains.