The Bilstein B4 04-10 BMW X3 Rear Twintube Strut Assembly is a twin-tube strut assembly designed specifically for the 2004-2010 BMW X3. It is designed to provide improved handling and stability, as well as increased ride comfort. The strut assembly is constructed from high-quality materials, and features Bilstein’s patented monotube gas pressure technology for superior performance. The assembly includes a dust boot, a bump stop, and a spring seat. It is backed by Bilstein’s limited lifetime warranty.