SRAM, GX 1X11, Rear derailleur, 1X11sp., Long cage, Black

X-Actaution for precise and dependable 11-speed performance
X-HORIZON design reduces shift force and ghost shifting
TYPE 2.1 technologies: ROLLER BEARING CLUTCH and CAGE LOCK
12-tooth X-SYNC™ pulley wheels
Large upper pulley offset automatically adjusts chain gap