If you find a gap, measure it by sliding a feeler gauge under the ruler.
Without minor lip
Type code
Furthermore, iridium spark plugs are designed to withstand high temperatures and extreme conditions inside the engine. This means they are less prone to fouling and misfiring, even under intense driving conditions. This reliability makes iridium spark plugs a great choice for performance cars or vehicles that are used for towing or heavy-duty applications.
ERIKS type M (type B according to the DIN standard) has a single metal casing and rubber sealing lip. Since the casing is made of metal, it must be fitted in a well-finished, undamaged groove. Large volumes of oil seals with metal casings are often cheaper, which is why they are often used as original equipment in machines. However, if an oil seal has to be replaced, types with a rubber exterior (type R or RST) are easier to fit. Type MST is similar to M and commonly used. The difference is the dust lip in the MST oil seal that prevents dust and dirt reaching the sealing lip, and extends its service life in dusty environments.