External chainringShimano Dura-Ace FC-R9100 with high quality construction for hollow race to save weight and increase stiffness for optimal power transfer. New tooth design for smoother shifting.The Shimano Dura-Ace FC-R9100 outer chainring offers optimal power transfer through a reinforced design on its unique, asymmetrical four-spoke spider web structure. The new R9100 groupset meets the highest standards of stiffness and durability.With a new 4-spoke design, the Shimano Dura-Ace FC-R9100 chainring is the choice of the world's best climbers, sprinters and time trialists. For weight savings without sacrificing stiffness.New 4-spoke design saves weight without sacrificing stiffnessDura-Ace FC-R9100 rangeMaterial: AluminumHollowglide: yes4 armsCenter distance 110mmCompatible with 2x11 Speeds