Shock absorbers are mostly accessible at the Bilstein shocks. These shock absorbers are basically oil pumps strategically placed in between the wheels and the frame of the car. The shock absorbers upper mount is connected to the frame while its lower mount is connected to the axle, near the wheel. When encountering a bump in the road, the springs coils and uncoils. From this coiling and uncoiling, the energy of the spring is then transferred to the shock absorber by means of the upper mount, down through the piston rod and into the piston.

Majority of standard shock absorbers out in the market nowadays have a damping characteristic mainly defined by the flow of oil through the piston assembly. The Koni worked out on this and added on a twist to come up with a new Koni shock. It combines the features of standard shock absorbers with their own invention, the Frequency Selected Damping (FSD). Koni added a special valve that is able to control the oil flow parallel to the one in the piston rod. This parallel oil flow is thus closed by the FSD feature. This gives a rise in the damping force, which is almost linear with the time the piston moves in one direction.

In simpler terms: the FSD feature is a hydraulic amplifier that delays the build up of pressure. Through this, an extra tuning option is created and vehicle owners can get the best car handling and ride comfort possible. Since the FSD is integrated into the hydraulic valve system, no additional cables, sensors and other electronic devices are needed for it to function.