CeramicSpeed pulley wheels reduce friction, last 3-5 time longer than stock high-end pulleys, and are designed to work with less drag.Precision machined aluminum narrow-wide pulleysHardened racesIncludes: (2) 14 tooth pulley wheels and CeramicSpeed Bearing Oil 15ml bottleCompatible with Shimano XT M-8100 series and Shimano XTR M-9100 seriesCompatible with the stock range of cassette sizes, up to a 51t cassette.Premium Grade 3 Silicon Nitride Ceramic ballsHand built in DenmarkItem SpecificationsDrivetrain Speeds12Fits BrandShimano CeramicSpeed Pulley Wheels Pulley Assembly EAN: 5711050072514