This is an NOS FR500S brake rotor brackets that we have left over from the FR500S days. They are brand new.  They are dimensionally the same as FR500C with 14" brakes.  These brackets will mount the Brembo F50 caliper to a Mustang (CALIPER IMAGE INCLUDED FOR REFERENCE ONLY). They will also work to mount Stoptech calipers on a Mustang.  If you used Stoptech calipers, you NEED to use FR500C, FR500S, or Boss S rotor hats.  These will not work with Stoptech hats!  The rotor offset will be off by ~1.2mm.