Sram GX Eagle 12-Speed Rear Derailleur SRAM's new GX EagleT rear derailleur features an updated cage architecture that improves chain management. Designed to work with the new 10-52t cassettes, it's also backwards compatible for the 10-50t versions. Key Features Backwards compatible, works with both 10-50t and new 10-52t cassettes Updated cage architecture provides better chain retention and precise shifts Comes in GX EagleT master colorway as part of EagleT Colorsystem and goes with all colors of Eagle cassettes & chains - from Black to Gold to Rainbow, to HardChrome and new Copper Specification Speed (RD): 12s Cable pull ratio: X-actuation Cage (RD): Long Max tooth: 52 Color (RD): Lunar Pulley bearings material: Steel Cage material (RD): Aluminum