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

Here is Why You Need An Adapter

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

Israel

In Israel, outlets of type C and H are in use.

Type C

Type H

Guinea

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

Type C

Type F

Type K