You Do Need power plug adapter while traveling from Argentina to Eritrea.

Here is Why You Need An Adapter

The outlet and plug type used in Eritrea are C and L and in Argentina are C and I. This is how they look like.

Argentina

In Argentina, outlets of type C and I are in use.

Type C

Type I

Eritrea

In Eritrea, outlets of type C and L are in use.

Type C

Type L