Wolf Tooth Components 42T Drop-Stop Chainring: for Shimano Road 110 Asymmetric 4-bolt 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