For the 4 series, 2G swivels completely to variants with an M18 thread. Nevertheless, the M14 variants will continue to be maintained and almost all development steps will be transferred to both types. For example, the 2G 57-4 * spark plug is used in the area of the M14 variant - it is gradually replacing all previous variants. The spark plug is characterized by an advanced welding process, which leads to a long service life and prevents failures.
