hi

I need help. My owners manual lists 6 different plug(spark) #'s. What is the purpose/benefit of each?

The manual lists the following:
Bosch

H9DC,H9DCO,H9D


Beru:

14K-9DU,14K-9DUO,14K-9DPU
* 2 3's are listed for champion also can anyone tell me the meaning of thes #'s

I have a 103 engine
THANKS