SRAM NX Eagle Rear Derailleur & Cassette, 12 Speed, BlackThe 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. The Type 3 ROLLER BEARING CLUTCH provides quiet, consistent performance and durability. Eagle pulley technology provides greater efficiency, crisper shifting and quieter operation Designed to be used with