Sram Gx Eagle, Rear Derailleur, 12Sp., Long, Black* Larger, 14 tooth X SYNC lower pulley allows for a 10 to 50 tooth cassette, and also adds to Eagles overall smooth pedaling feel* Type 3 ROLLER BEARING CLUTCH features a smoother torque curve for a quieter, more consistent operation and feel* CAGE LOCK has been moved back and out of the way, protecting it from trail debris. * Redesigned, robust mounting system further improves the Eagle derailleurs performance and overall durability.