An interesting feature of Audi's new TT vehicle is its semi-active primary suspension system enabled by magneto-rheological (MR) fluid technology that allows continuously variable real-time suspension damping control. The suspension system is supplied by Delphi Corp. and is based on technology from Lord Corp. Although it can be used for other applications including seismic damping in buildings, damping of bridges against strong winds, and controlled dampers in prosthetic devices designed to provide users with tactile feedback, MR fluid technology's main market is the auto suspension system. MR-based components are now operating in hundreds of thousands of vehicles all over the world.