The Bilstein 17-20 Audi A4 B8 Performance Plus Shock Absorber is designed to provide superior performance for your Audi A4 B8. This shock absorber features a monotube design for improved damping response and long-term performance. It also features a progressive rate spring and a high-pressure nitrogen gas charge for improved ride comfort and stability. The shock absorber is designed to reduce body roll, improve steering response, and reduce brake dive. This shock absorber is perfect for those who want to upgrade their suspension system for improved performance and handling.