Shimano Dura-Ace FC-R9200 chainrings are constructed with high quality aluminum and are compatible with FC-R9200 and FC-9200-P 2x 12-speed cranksets. Asymmetric 110 BCD Compatible with HG 12-speed chains Aluminum with anodized finish provides durability and light weight Hollowglide technology provides high rigidity and cuts down on weight while maintaining strength Offers better power transfer and quicker, more precise front shifting 52t outer chainring is for use with 36t inner chainring Specifications Chainring BCD 110 Shimano Asymmetric Color Black Defined Color Black Drivetrain Speeds 12 Material Aluminum Ring Position/Type Outer Round or Oval Round Tooth Count 52