QA1 understands that you need a shock that is designed specifically for your Mustang. Available in single adjustable, drag “R” series and non-adjustable valving options, these shocks are made in the U.S.A. and are 100% dyno tested and serialized, ensuring they are of the highest quality.Made in the U.S.A. Easy, Bolt-In Installation No Cutting or Welding Needed Non-Coil-Over Lightweight Aluminum Bright Anodized Body Stock Mount 100% Dyno Tested and Serialized Rebuildable and Revalveable by the QA1 Factory or QA1 Authorized Service Centers