Sram Nx

The Sram NX X-Horizon rear derailleur provides the same smooth, reliable shifting as XX1 - from the larger offset of the upper shifting roller to the 12-tooth X-Sync Horizon chain idler. Because unwanted chain movement is a thing of the past, the X-Horizon allows for faster shifts, eliminates "ghost shifting" and reduces shifting force and beating chains. Cage Lock Horizon technology makes rear wheel removal and installation easier than ever.

The X-Horizon design reduces shifting force, "ghost shifting" and beating chains.
X-Sync Horizon chain idler with 12 teeth
Fully compatible with all Sram MTB 1xHorizon drives
The most affordable 1x rear derailleur with a wide range of functions