Eibach offers a number of different coils categorized by spring rate and length. The coil on the right is rated at 500 pounds per inch, while the other is a 200-pound spring. Notice the difference in thickness of the coil wire. King recommended dual-rate coils. The lower coils on our shocks are 350-pound and the uppers are 250-pound. This is considered a light setup and should put the shock in the middle of its travel with the static weight of our truck.