Designed to fit 4-arm 110 Asymmetric BCD Shimano Road Cranksets. Its proprietary design has an ovality of 10% and a timing of 112 degrees after top dead center which provide the beneifits of an oval ring such as greater rear wheel traction without the traditional downsides of oval rings. These rings feature the patent pending Drop-Stop asymmetrical tooth design for the best in wear life, mud clearance, and chain retention.The simplest way to explain the way these rings feel is having 2 teeth less in the weak part of your pedal stroke and 2 teeth more where you have the most powerFeatures Wolf Tooth's Drop-Stop tooth design for maximum chain retentionDrop-Stop chainrings are designed for use with 1x9, 1x10, 1x11 and 1x12 drivetrainsCompatible with all 10-, 11-, and 12-speed chains, with the exception of Shimano 12-speed chainsShimano 12-speed chains require the use of Wolf Tooth's Shimano 12-speed specific chainringsIf using a 9-speed drivetrain, use a 10-speed chain, which will provide a tighter fit for better chain retentionMade from 7075-T6 aluminum for long lifeUse of a clutch-style rear derailleur is recommendedItem SpecificationsChainring BCD110 Shimano AsymmetricColorBlackDefined ColorBlackDrivetrain Speeds10Drivetrain Speeds11Drivetrain Speeds12Drivetrain Speeds9Ring Position/TypeChain Retaining Single RingTooth Count40 Wolf Tooth Elliptical Shimano 110 Asymmetric BCD Chainrings Chainring UPC: 812719022354