The Bilstein 13-17 BMW X3 B3 OE Replacement Coil Spring - Rear is a replacement coil spring designed to replace the original equipment coil spring in the rear of the BMW X3 from 2013-2017. It is made from high-quality steel and is corrosion-resistant for long-term durability. It is designed to provide a comfortable and smooth ride for the vehicle, and its special design helps to reduce body roll and improve handling.