SRAM Rear Derailleur GX Eagle 12 speed Lunar Max 52TThe GX Eagle Rear Derailleur gets the job done with a thoughtfully designed cage architecture that improves chain management. Mounting system and re positioned Cage Lock offer greater durability Sealed cartridge pulley bearings Backwards compatible, works with both 10 50t and 10 52t cassettes Updated cage architecture provides better chain retention and precise shifts Comes in GX Eagle master colorway as part of Eagle Colorsystem and goes with all