Sram nx1 11 speed rear derailleurthe sram nx1 11 speed rear derailleur provides the same smooth reliable shifting action as xx1from the larger upper pulley offset to the 12 tooth x sync pulley wheels by eliminating unwanted chain movement x horizon shifts faster puts an end to ghost shifting and reduces shift force and chain slap and with cage lock technology wheel removal and installation are easier than ever features x horizon design that reduces shift force ghost shifting and ch