Borg Warner S400 series downpipe flange. Designed to fit the 20* taper 1.32 S400 exhaust housing outlet. If you have a different A/R housing with  a flat surface measuring 4 5/8" OD you will want to use our standard 4" V-band flange (female side) and 4" V-clamp. We offer this flange in Aluminum for the ultimate in light weight exhaust for your Street/Race car. Also available in Steel and Stainless steel. If you are running an exhaust housing other than the standard 1.32 a/r this will not work