These rings are designed for Surly OD cranks, but are compatible with other 5-bolt 94 BCD cranks. These rings feature the patent pending Drop-Stop asymmetrical tooth design for the best in wear life, mud clearance, and chain retention. Made from 7075 Aluminum for long life. Not compatible with 9 speed chains. Features Wolf Tooth’s Drop-Stop tooth design for maximum chain retention. Optimized for use with 10, 11, and 12 speed chains or 10 speed chain. Color: Black. Material: Aluminum. Chainring BCD: 94. Defined Color: Black. Ring Position/TYPE: Chain Retaining Single Ring. Drivetrain Speeds: 10. Drivetrain Speeds: 11. Drivetrain Speeds: 12. Tooth Count: 28.