Shimano Belt Drive CassetteThe Continental Belt Drive Cassette is a drivetrain sprocket that's compatible for use with the Continental Belt Drive (CBD) system.The CBD sprockets made of aluminium and stainless steel provide a balance of stability and optimal weight. Sprockets up to 28 teeth are made from high-strength stainless steel for reduced wear and tear and improved stability. Sprockets with 34 teeth are made from aluminium for weight reasons and have a special surface finish to reduce wear.Features: Tooth Count: 20T Drivetrain Compatibility: Continental Belt Drive (CBD) Belt Drive OnlyBuy Continental Components from Chain Reaction Cycles, the World's Largest Online Bike Store.