Compact size is perfect for applications with limited space. 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. Hands down, Borla's XR-1? raceline parts offer a good balance of sound and power.