Eibach HELPER spring. Essentially a zero rate spring to take up slack. A tender spring is often confused with a Helper springs. The Tender spring has a specific rate and length for tuning, the Helper spring is universal. Helper or Tender springs must be used with a spacer.
Eibach springs are made on German machines both in the USA and in Germany, however all Eibach springs have a lifetime guarantee against sagging, rate change, or any manufacturing or material failure. Lifetime guarantee. Compare.