The Bilstein B4 Series 19-135021 is a high-quality gas pressure twin-tube shock absorber designed to restore your vehicle's original handling and stability. Engineered specifically for the BMW 3 Series (E90/E92/E93) and 1 Series (E81/E82/E87/E88), this shock absorber ensures a smooth ride and optimum road adhesion. Key Features: Constant damping under any load, high power reserves for maximum safety, and OE-quality standards. This item is sold as a single unit. Recommended to be replaced in pairs. Included components: 1 x Rear Shock Absorber (Part No. 19-135021). Professional installation is recommended.