The Bilstein 14-19 BMW 640i xDrive B4 OE Replacement Shock Absorber - Rear is a high-quality replacement shock absorber designed to replace the original equipment shock absorber on the BMW 640i xDrive B4. It features a monotube design which helps to improve ride quality and reduce body roll. The shock absorber is constructed from a heavy-duty steel body and features a corrosion-resistant finish for long-term durability. It is designed to provide improved handling and stability, as well as a smoother ride. The Bilstein 14-19 BMW 640i xDrive B4 OE Replacement Shock Absorber - Rear is an ideal replacement for worn or damaged shock absorbers.