The Koni Special Active Shock FSD 03-10 BMW X3 (E83) Rear is a high-performance shock absorber system designed to provide superior handling and stability for the BMW X3 (E83). It features a Frequency Selective Damping (FSD) technology that automatically adjusts the damping force of the shock absorbers depending on the road conditions. The FSD technology also helps reduce body roll, improve steering response, and reduce braking distances. This shock absorber system is made from high-quality materials and is designed to last for a long time.