1. Steel shell: The lower part of the steel shell is a fine thread, which is used to match the spark plug hole of the cylinder head, and the upper part has an outer hexagonal nut for the spark plug sleeve to tighten or screw out the spark plug.
2. The metal rod is the central electrode. The lower end of the metal rod is in contact with the upper end of the central electrode through the conductor vitreous, and the upper end of the metal rod is fitted with a wiring nut.
3. There is a high alumina ceramic insulator between the steel shell and the central electrode, so that the central electrode is insulated when energized.
4. The lowest part of the steel shell is equipped with curved side electrodes.
5. There is a copper washer in the middle of the outer part of the steel shell.