CeramicSpeed Oversized Pulley Wheel SystemThis CeramicSpeed Oversized Pulley Wheel System is developed for performance optimisation, and the watt savings start at 2.4 watts. The cage is made from carbon fibre and reinforced PA while the 17-tooth pulley wheels are made from aluminium and mounted with high quality CeramicSpeed bearings.This revolutionary OSPW System is developed, produced and assembled by hand in Denmark. This plug-and-play product is the result of an in-depth development process and has been designed for optimal performance. Created to answer the need for less friction (as much as 60%), increased speed and a more efficient drivetrain. This OSPW System helps you ride any distance comfortably. The optimisation of your drivetrain with the new CeramicSpeed OSPW System delivers access to the industry leading efficiency. The use of high quality materials means this system will outlast other commonly used pulley wheels on the market. Like all other products delivered by CeramicSpeed, this product has undergone a thorough testing program and is used by professional triathletes Tim Don and Tyler Butterfield. Features:Material: Carbon/PA Cage, Aluminium Pulley Wheels Shimano Compatible 10 or 11-speed Weight: 55gMaintenanceIts important that you properly lubricate your bearings in order to ensure optimal performance and maximum longevity. Add oil to the outside of the bearing seal, so that oil can penetrate the bearing. Do this when you lubricate your chain, or if you have washed your bike or have been riding in wet or muddy conditions. Buy CeramicSpeed Components from Chain Reaction Cycles, the Worlds Largest Online Bike Store.