SRAM Red Rear Derailleur WiFli Medium Cage, 32 Tooth Largest Cog C2Top of the line rear derailleur with generous use of carbon fiber and titanium for maximum performance at minimal weight. Graphics match SRAM Red eTap electronic components Carbon fiber and aluminum construction Ceramic bearing pulleys Titanium hardware Item Specifications Cage Length Medium Chain Wrap Capacity (teeth) 37 Color Black Drivetrain Speeds 11 keyword search RD4621 Largest Cog 32 Rear Der Shifter Compatibility SRAM Exact Actuation Rear