The Bilstein 04-07 BMW 525i B3 OE Replacement Coil Spring - Rear is a direct replacement for the original equipment (OE) coil spring found on 2004-2007 BMW 525i models. This spring is designed to provide an improved ride quality, enhanced handling, and improved stability. It is made from high-quality materials and is backed by Bilstein's limited lifetime warranty. This replacement spring is the perfect solution for worn out or damaged OE springs.