DC Sports Stainless Steel Headers come in 3-1, 4-1 One-Piece, and 4-2-1 One-Piece & Two Piece. Every system is dyno-tested for maximum performance. Made 100% 304 Stainless steel construction including the flanges (polished or brushed), or mild steel with ceramic coating. In addition, CNC-machined flanges eliminate leaks. All systems are CNC mandrel bends with precision-welded fittings to deliver perfect fit. Most importantly, equal length primary piping ensures optimum tuning of systems for more power across rpm range.