The Bilstein 18-19 BMW X3/2019 X4 B4 OE Replacement Shock Rear is a high-performance shock absorber designed to replace the original equipment shock on the BMW X3 and X4. It features a monotube design for superior performance, and is constructed from high-quality materials for long-lasting durability. The shock is tuned to provide improved handling and a smoother ride, while still providing the necessary control for a safe and enjoyable driving experience.