CN-9100 XTR/Dura-Ace 12 Spd.The Shimano CN M9100 features an extended inner link plate that connects seamlessly with chainring teeth for highly efficient drivetrain performance. Its design offers a reduction in natural vibrations normally caused by the inner and outer chain plates rolling onto the chainring. It provides better chain engagement, stronger retention, and smoother pedaling. Enhancements to shifting performance Easy connect Non reusable Smoother driving even over