DC Sports HHC5011 4-2-1 Header with Ceramic Coating (2 Piece), Silver Dyno tuned and tested against the competition for maximum performance CAD-rendered design with threaded flanges for easy installation 4-2-1 design emphasizes low and midrange power for street/strip applications CNC mandrel bends with robotically-welded fittings deliver perfect fit CNC machined flanges and O-ring seals eliminate leaks