Feature●PREMIUM ALUMINUM ALLOY: This bike derailleur pulley adopts quality aluminum alloy and ceramic material to ensure durable to use. It also can reduce drag force which can improve cycling efficiency.●WIDE ADOPTIONS: It is suitable for 4 / 5 / 6 mm guide wheel screws and offers you a better cycling experience.●EXQUISITE CRAFTSMENSHIP: It made of CNC processing that ensure the premium quality.●EASY INSTALLATION: This jockey wheel rear can be applied for most mountain bike and supplied for various speed shifting. With two bike guide roller and hole adapter tube are easy to install.●GUARANTEE: Our product have 180 days warranty, if you have any question about this product, please feel to contact us, we will try our best to help you solve your problem.Description