The NX Eagle rear derailleur features the proven SRAM 1x-specific X-HORIZON design. The larger, 14-tooth X-SYNC lower pulley easily facilitates 11- to 50- and 10- to 50-tooth cassette capacity, and also adds to NX Eagle&';s overall smooth-pedaling feel Mounting system and re-positioned Cage Lock offer greater durability Eagle pulley technology provides greater efficiency, crisper shifting and quieter operation Designed to be used with Eagle 12-speed chains Long cage with 50 tooth max capacity Rear Derailleur Mount Type: 10x1 Standard Drivetrain Speeds: 12 Cage Length: Long Largest Cog: 50 Color: Black Rear Der/Shifter Compatibility: SRAM X-Actuation Designed for ebike: Yes