NGK U4008 / 48157 Ignition Coil Genuine NGK ComponentEssentially the operating principle is the same for all types of ignition coils- whether the classic can-type coil, or in a coil rail system. The device contains two copper wire windings and a laminated iron core. The copper wires are insulated to prevent short circuits. The battery current fed through the primary winding produces a magnetic field whose strength is further increased by the iron core. When this circuit is opened, the magnetic field collapses, inducing a high voltage pulse in the secondary coil.U4 Type Ignition CoilOne ignition cable is required for each coil The NGK ignition coil of the Type U4 is a pencil coil with double spark technology. As a poloidal coil or coil-on plug, each provides two spark plugs with high voltage.BOX DIMENSIONSHeight (mm): 100Width (mm): 170Length (mm): 110If you are unsure as to whether this is the correct part for your vehicle, please don’t hesitate to contact us. Alternatively please use the cross reference table above.