You Do Need power plug adapter while traveling from Congo to Isle of Man.

Here is Why You Need An Adapter

The outlet and plug type used in Isle of Man are C and G and in Congo are C, D and E. This is how they look like.

Congo

In Congo, outlets of type C, D and E are in use.

Type C

Type D

Type E

Isle of Man

In Isle of Man, outlets of type C and G are in use.

Type C

Type G