The Shimano Ultegra RD-RX805 Di2 GS Rear Derailleur in black is a high-quality component designed specifically for road bikes with 11 speeds. This rear derailleur is from the renowned brand Shimano, known for their precision and durability in cycling components. Its medium cage length makes it suitable for a wide range of gear ratios, ensuring smooth and reliable performance on your rides. Perfect for cyclists looking to upgrade their road bike with a top-of-the-line rear derailleur from a trusted brand like Shimano.