GX 1 x 11 X-HORIZON Rear DerailleurDescription The SRAM GX X HORIZON rear derailleur is engineered for smooth, reliable shifting action from 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 reduces shift force, ghost shifting