Delphi GN10304 Plug-Top Ignition Coil Delphi uses winding process techniques to control the length of wire between adjacent windings. That is important since more length means greater voltage differences, and can create more pressure that could break down the insulation and wire coating Delphi ignition coils are engineered to OE specifications; built with the benefit of more than 100 years of Delphi's OE heritage, Delphi's coils are designed and endurance tested to resist the common stresses that cause failure Delphi's ignition coil is designed with proven materials, such as quality wires and wire coating that resists the cracks, pin holes and imperfections that most often lead to failure issues Epoxy vacuum techniques reduce air bubbles in the epoxy, because having fewer air bubbles increases the epoxy's insulation quality and reduces the chances of energy punch through failures