The Bilstein B6 2003 BMW Z4 2.5i Rear 36mm Monotube Shock Absorber is designed to provide superior performance and handling for your BMW Z4. It features a 36mm monotube design that provides increased damping response and stability, as well as a self-adjusting, deflective disc valve that ensures consistent performance. The shock absorber is constructed from high-quality materials and is corrosion-resistant for long-lasting durability. It is also designed to reduce body roll and improve overall ride comfort.