All BORLA ProXS Mufflers utilize a straight-through design; they do not use chambers or baffles that slow down the flow of exhaust. As such, every one of the universal mufflers are reversible. 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. Reversible design for installation flexibility. Recommended for car, SUV and truck applications.