Dual inlet and dual outlet. Internal X - Pipe for increased performance and improved sound. Notched necks for easy clamp - on installation. Reversible design for installation flexibility. High - quality T - 304 Stainless steel will never rust. 100 welded construction for strength. Free Flow design for improved performance. High - temperature continuous - filament fiber (CFF) acoustic material for sound control. Natural mill finish can be brushed or polished prior to installation.