This new belt tensioner brace is intended for use on 2005-09 Mustangs and F-150 trucks with an aftermarket supercharger installed. The stock belt tensioner is cast aluminum and has been known to bend and even break under extreme driving. The Edelbrock Steel Belt Tensioner Brace is an inexpensive solution to this common problem. It simply bolts on to your stock tensioner and prevents any deflection of the cast arm. This brace is already included in the Brenspeed Turn Key E-Force Supercharger Packages.