Self leveling, rear hydro pneumatic shock. A strut is a special type of shock absorber that is designed to rotate with the motion of the steering, and directly connect to the steering knuckle. Because the strut rotates on an axis, the coil spring is integrated into the design, and mounted as a complete independent assembly with strut mounts and a bearing that the assembly rotates on. Signs of worn out shocks include a bouncy ride when driving, as well as more noticeable body roll in turns. Routine inspections will indicate if your shocks are leaking or damaged.