The Bilstein B4 2003 BMW Z4 2.5i Rear Twintube Shock Absorber is a high-performance shock absorber designed to provide superior handling and stability for your BMW Z4 2.5i. This shock absorber features a monotube gas pressure design that offers improved damping control and a consistent, comfortable ride. It also features a self-adjusting deflective disc valve and a high-pressure nitrogen gas charge for maximum performance. With its corrosion-resistant zinc finish, this shock absorber is built to last and is sure to provide your BMW Z4 2.5i with improved handling and stability for years to come.