Developed for truck applications and other applications that require a long body muffler. Previous part number was 19131347. This muffler is considered an "S-Type" muffler when compared to the 401158 and used on the same application. Notched necks for clamp-on installation. Reversible design for installation flexibility. High-quality T-304 austenitic 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.