Alternatively, one of the implements 330, 331 can constitute a tool which is used to mount or remove a spark plug. [0191] FIG. 4 shows a profiled (e.g., hexagonal) head 332 which is provided on or is connectable with the input element 301 and can be received in a complementary socket of the implement 330. [0192] FIG. 4a shows that the accessible end of the input element 301 can be provided with a