The sram nx x horizon 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 x horizon design that reduces shift force ghost shifting and chain slap 12 tooth x sync pulley wheels fu