Shimano Ultegra R8101 12-Speed Cassette The Shimano Ultegra R8101 12-Speed Cassette brings precision shifting and peak performance to your drivetrain. Designed with a new tooth profile, this cassette delivers faster, smoother shifts even under maximum pedaling force, making it an ideal choice for both racing and everyday rides. Whether you��re using Di2 or a mechanical shifting system, the refined 12-step gear combination offers optimized efficiency and acceleration for every situation. Key Features: New Tooth Profile : Refined to accommodate both Di2 electronic and mechanical Shimano drivetrains, ensuring smoother shifts across all gears. 12-Speed Compatibility : Works with Shimano's 12-speed drivetrains, ensuring peak performance with the latest tech. Refined Gear Combinations : Offers e