Improved performance and longevity: The JRC Components 11T ceramic pulley wheels outperform standard Delrin pulley wheels and offer a much higher mileage due to the slow-wearing nature of the CNC Machined 7075-T6 Aluminum. The use of machined aluminum in their construction enhances their durability, ensuring they can withstand prolonged use without compromising performance. Lightweight and efficient design: Weighing only 17g per set (8.5g per wheel), these jockey wheels offer a lightweight solution that reduces rotational mass. This design choice contributes to improved responsiveness and overall efficiency of your drivetrain, resulting in a smoother and more enjoyable riding experience. Personalization options: The 11T ceramic pulley wheels are available in 11 anodized colors, allowing you to customize the appearance of your drivetrain. This feature enables you to match your bike's aesthetics or express your personal style while benefiting from the enhanced performance and longevity provided by these 11T pulley wheels Improved shifting performance: The hybrid ceramic bearings incorporated in the JRC Components 11T ceramic pulley wheels contribute to smoother rotation while the aluminum contributes to more precise shifting. The reduced friction and enhanced bearing efficiency result in quicker and more accurate gear changes, providing an improvement in the overall performance of your drivetrain. "11T Ceramic Pulley Wheels Upgrade your drivetrain with our JRC Components 11T ceramic pulley wheels! Performing to a much higher standard than standard Delrin pulley wheels & ensuring much higher mileage due to the slow-wearing nature of machined aluminum, our 11T ceramic pulley wheels offer an experience like no other! Spec: Compatible with 9/10/11 speed chains (All systems using 11T pulley wheels: Shimano / Sram / Campagnolo) Brass adaptor included allowing for use with Sram m4 bolt system Crafted from billet aluminum, CNC Machines, and Anodised Hybrid ceramic bearings add to the pulley wheels for longevity and lessened friction. Fully sealed and packed with grease to ensure flawless use all year round Ultra lightweight,17g per set (8.5g per wheel) Available in 11 anodized colors Compatible with these Rear Derailleur Types: Shimano 9/10/11 speed road systems (105, Ultegra [Di2], Dura-Ace [Di2], etc...) SRAM 10/11 speed mechanical dual road systems (Apex, Rival, Force, Red) Campagnolo 9/10/11 speed (Centaur, Athena, Potenza, Chorus, Record [eps], Super Record [eps], etc...) Included: 2x 11T Ceramic Pulley Wheels 4mm adapter for use with Sram derailleurs "