Billet CNC Machined aircraft grade aluminum is machined into the highest quality suspension products right here at JHR. Our spherical bearing kit for the 8.8" Ford Mustang rear is precision machined to tolerances that are probably not necessary but we want our customers to be completely satisfied with every purchase from JHR. This kit is suitable for all types of racing use and if used on a street driven vehicle there will be a signicant increase in road noise (NVH) We do, however, use a Teflon lined commercial grade Spherical bearing to minimize friction and wear from constant load and motion. We ONLY use AMERICAN MADE bearings in our kits. There are some places where saving a buck is not worth the risk. With our highly qualified staff of designers and machinests we are able to bring our customers a value that most other companies can only dream about. The entire staff at JHR is on a mission to be the best. As with all JHR manufactures parts this one has a lifetime replacement warranty. See warranty details on our website.