Shimano RD-L522 is a high-quality rear derailleur designed for smooth and precise gear shifting on various types of bicycles. It is compatible with both single, double, and triple front chainwheels and can accommodate a wide range of freewheels, including those with up to 28 teeth. The RD-L522 features adjustable B-tension and stroke to ensure optimal performance with different frame and drivetrain configurations. It also has a durable construction and is easy to install and maintain.