The Bilstein B4 2001 BMW 525i Base Front Twintube Strut Assembly is a high-quality replacement strut assembly designed to provide improved handling and stability for your BMW 525i. It features a twin-tube design that provides superior damping performance and durability, and an adjustable spring preload that allows you to customize the ride height and handling characteristics of your vehicle. The strut assembly is crafted from high-quality materials for long-lasting performance and is backed by Bilstein’s limited lifetime warranty.