Delphi GN10369 Pencil Ignition Coil Delphi uses winding process techniques to control the length of wire between adjacent windings; more length results in greater voltage differences, which can create more pressure that could break down the insulation and wire coating Delphi ignition coils, which are engineered to OE specifications, are designed and endurance tested to resist the common stresses that cause failure Delphi backs its ignition coil design with proven materials, such as high quality wires and wire coating that resists the cracks, pin holes and imperfections, that most often lead to failure issues Delphi uses an epoxy vacuum technique to 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