Elevate your cycling experience with the CeramicSpeed OSPW RS Pulley Wheel System, expertly designed for Shimano Dura-Ace and Ultegra models. This innovative system showcases a modern and angular design, seamlessly integrating into contemporary bike aesthetics. Not only does it enhance the visual appeal of your setup, but it also offers unparalleled performance through its cutting-edge technology. The reinforced cage provides exceptional strength and durability, ensuring longevity and reliability on your rides.Injection Molded Carbon Fiber reinforced PA cage for enhanced strength and durabilityAnodized aluminum 5-spoke pulley wheels, featuring 13-tooth upper and 19-tooth lower configurations, deliver lightweight yet robust performanceGrade 3 Silicon Nitride ball bearings are engineered to be 400% smoother, 128% harder, and 58% lighter than standard steel counterparts, significantly reducing frictionFour customizable spring tension settings allow for optimal setup tailored to your riding styleCompatible with Shimano Road Dura-Ace and Ultegra 12-speed rear derailleurs, ensuring a perfect fit for your bike