Shift Boot Retainer. Securely retain your manual Mustang's shifter boot in place with this Shift Boot Retainer . It also allows you to use a wider variety of aftermarket shift knobs. Quality Materials. This Shift Boot Retainer is a made from solid billet aluminum and is completed in a black anodized finish for good looks and durability. Application. This Shift Boot Retainer is designed to fit the 2005 to 2014 manual Mustangs or Mustangs equipped with a 12mm x 1.25 thread pattern shift handle. Excludes 2011+ Shelby GT500s.