Campagnolo Chorus 11 Speed Cassette, 11-23, 11-25, 12-27 Ultra-Shift Teeth Design means every sprocket tooth is designed and placed to perform a specific function, such as raising or lowering the chain or giving maximum power transmission to the wheel Ultra-Shift Synchronization sprocket tuning allows for maximum shifting performance without hesitation -- it's fast, accurate and quiet, even under stress Reinforced mounts for second and third triplets offer greater sprocket set rigidity, performance and precision Steel construction with nickel-chrome surface treatment reduces chain/sprocket friction and extends sprocket life Light alloy lockring for weight savings