CeramicSpeed pulley wheels reduce friction, last 3-5 time longer than stock high-end pulleys, and are designed to work with less drag. Premium Grade 3 Silicon Nitride Ceramic balls Hand built in Denmark Precision machined aluminum narrow-wide pulleys Coated races increase bearing service life by increasing hardness of race and reducing corrosion Includes: (2) 14 tooth pulley wheels and CeramicSpeed Bearing Oil 15ml bottle CeramicSpeed products with coated bearings include a 6-year warranty Specifications Drivetrain Speeds12Fits BrandSRAM