Our OE quality shackle sets are made from precision tooling, exactly like originals and exceed GM material specs. Manufactured by QS-9000 and ISO/TS16-944 certified OE suppliers. Plates are precision stamped from high grade medium carbon steel and zinc plated. Special shackle bolts are accurately shouldered, also of high grade medium carbon steel, then "thru hardened" to the same Rockwell hardness as original. Competitors use a lower grade mild steel, with poor quality stamping tooling, and the bolts as lab tested had "zero" hardness! Our competitors bushings use a low grade rubber, where our OEM bushings use a blend of rubber compounds found in today's higher end world cars. The result - superior handling, outstanding ride quality, long life and a shackle that looks and performs exactly like factory original. Suitable for street and sport applications. Correct Marsden style nuts included. Competively priced with the incredible junk out there. You and your customers need the peace of mind Classic Suspensions superior line of certified OE Manufacturer made suspension products can provide. Assembled. . Officially Licensed GM Restoration Parts.