Stepping up the shifting game, the Shimano M615 Deore rear derailleur integrates some of the best features available on modern derailleurs at a fraction of the price. Beginning with the Shadow design, this rear derailleur tucks the main body under the attachment point keeping it safely out of the way of approaching rocks and roots. Not content to just make a great-shifting derailleur that stays out of harm's way, Shimano added the Shadow Plus. The Plus means that it also has a tension clutch lever. This allows you to quickly and easily crank up the spring tension minimizing chain noise while still letting you easily remove the rear wheel. This 10-speed rear derailleur has all of the features of the top shifting derailleurs on the market at a fraction of the price.