The BOX Three Prime 9 X-Wide Rear Derailleur - 9-Speed Long Cage is a high-quality and durable component that is designed to provide smooth and precise shifting performance. With an extra-wide design, this derailleur can accommodate a wide range of gears, making it an excellent choice for riders who want to tackle any terrain. The long cage ensures that your chain stays in place, even during the most demanding rides. And, the sleek black finish adds a touch of style to your bike.