Shimano 105 CS-R7100 12 Speed Cassette Feature: A 12-speed cassette built for the 105 Di2 drivetrain Features 11-34T cogs for optimal gear combinations Combination of the 12 steel cogs optimize acceleration Smaller gears allow for better climbing efficiency Also compatible with 11-speed freehub bodies Shimano 105 CS-HG710 12 Speed Cassette Wide range cassette for varied terrain drop bar riding The 11-36T 12-speed cassette offers a wide gear range of 327%. From sprinting on the flats to steep climbs, you can choose the best gear ratio to suit every situation. Gear steps are optimized for pedaling efficiency, with the first eight cogs focusing on a natural and comfortable connection, and the largest four cogs allowing you to select from a wide range of gears while avoiding abrupt gear ratio changes. FEATURES Refined 12-step gear combination provides peak efficiency and accelerating performance for every situation Compatible with new 12-speed and road 11-speed FREEHUB body