CeramicSpeed OSPW RS Pulley Wheel System for Shimano Dura-Ace 9250/Ultegra 8150 - Aluminum Pulley, Carbon Cage, Black EA Cage Assembly

Injection Molded Carbon Fiber reinforced PA cage offers new levels of strength and durability Anodized aluminum 5-spoke 13-tooth upper and 19-tooth lower pulley wheels are light weight and durable Grade 3 Silicon Nitride ball bearings are 400% smoother, 128% harder and 58% lighter than standard steel balls normally used in the bicycle industry 4 customizable spring tension settings for optimal setup Compatible with Shimano Road Dura-Ace R9250 and Ultegra R8150 12-speed rear derailleurs