You Do Need power plug adapter while traveling from Gaza Strip to Guinea-Bissau.

Here is Why You Need An Adapter

The outlet and plug type used in Guinea-Bissau is C and in Gaza Strip are C and H. This is how they look like.

Gaza Strip

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

Type C

Type H

Guinea-Bissau

In Guinea-Bissau, outlets of type C are in use.

Type C