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. These lightweight billet aluminum smooth body shocks are made in the USA and offer easy, bolt-in installation. They are 100% dyno tested and serialized and serviceable and rebuildable by QA1 authorized service centers.