The Shimano RD-M8100 Tension & Guide Pulley is a high-quality replacement part designed for smooth and reliable performance on your mountain bike. Weighing just 19 grams, this pulley is lightweight yet durable, ensuring optimal functionality during your rides. The pulley features 13 teeth and is compatible with Shimano's 12-speed drivetrains, providing precise chain movement and efficient power transfer. Its sealed bearings offer smooth rotation, reducing friction and enhancing overall efficiency. Crafted with precision engineering and high-quality materials, the RD-M8100 Tension & Guide Pulley is a dependable component that will enhance the performance of your bike. Upgrade your drivetrain with this essential part from Shimano for a smoother and more enjoyable riding experience.