Wolf Tooth Components Drop-Stop Chainring: 36T x Shimano Asymmetric 110 BCD, for Shimano Asymmetric 4-Arm cranks, Black Not compatible with 9 speed chains Features Wolf Tooth's Drop-Stop tooth design for maximum chain retention May require modification if used with Shimano Dura Ace 9100 or Ultegra 8000 cranksets Optimized for use with 10, 11, and 12 speed chains Made from 7075 Aluminum for long life