The 10 speed Shimano 5700A 105 rear derailleur integrates the wide link design prominently featured in both Dura Ace and Ultegra derailleurs to not only promote quick shifting, but to preserve the pivots for greater durability and long term crisp shifting performance.It also features the ability to accept wide range 30t cassettes.The new derailleur is available in both short and medium cage lengths for double, compact, or triple crank configurations.