These reinforcement plates are made of 3mm(1/8”) steel and are great for anyone who is doing a suspension refresh on the aging 911 model years 1965-89. We have noticed on many chassis that the rear torsion bar mounting posts crack where they are mounted to the inner sheet metal. This is caused by worn bushings and a load transfer from the spring plate directly into the mounting bolt bosses. They were not designed to take this load. The solution was to reinforce the area sheet metal by tying in all four bosses and spread the load across a wider area. This kit is 2 brackets and one welding alignment plate to keep the correct spacing of the 4 bosses while welding. This kit was designed by Jamie Novak from the 911 forums on PP. Free shipping in the Cont. US., will ship internationally but buyer will pay all shipping costs, contact me first.