Adapter, MBRP Exhaust Adapter, Use 3.5in./ 5in. Hardware No Matter Size of System., 3 in. OD. to 5in.ID. Adapter AL, 3 in. OD. to 5in.ID. Adapter, Aluminized Steel., MBRP Exhaust Adapter,3.5in Outlet Diameter to 5in. Inlet Diameter., Universal., Exhaust Pipe Adapter.