You Do Need power plug adapter while traveling from Guinea to Vatican City.

Here is Why You Need An Adapter

The outlet and plug type used in Vatican City are C, F and L and in Guinea are C, F and K. This is how they look like.

Guinea

In Guinea, outlets of type C, F and K are in use.

Type C

Type F

Type K

Vatican City

In Vatican City, outlets of type C, F and L are in use.

Type C

Type F

Type L