BBB Cycling Derailleur Pulley Ceramic 11-Teeth and 13-Teeth Rear Shimano 11-Speed Jockey Wheels Roller Urban Road Bike MTB Bicycle RollerBoys Ceramic BDP-18, Black, One Size

QUICK SHIFTING PERFORMANCE: The RollerBoys will keep you rolling and make your bike ride so smooth that you will never stop anymore! The special 12 teeth narrow-wide profile gives you the perfect chain retention and makes sure you can shift to a higher gear with the speed of light! SHIMANO COMPATIBLE DERAILLEUR WHEELS: These bike pulleys are compatible with 11-speed Shimano GRX (810/815) SMOOTH CERAMIC BEARINGS : The RolleyBoys Ceramic Jockey Wheels are equipped with low friction Ceramic bearings and are lubricated with special Ceramic oil for even more smoothness and exceptional durability over CrMo bearings DURABLE AND STRONG: Made of Grivory EMS, this composite material has a 40% glass-fiber mixture which makes it extra strong and durable compared to other derailleur pulleys ALUMINIUM BUSHINGS: The RollerBoys Derailleur Pulleys have anodized Aluminium bushing for added stiffness and extra protection for your bearings