For use with battery chargers, curling irons, shavers, tooth brushes, and other electric appliances between 0-50 watts.
In many cases, you cannot use a voltage converter without an adapter plug! Even though the voltage converters have 2 rounded pins (as used in most of Europe), many outlets are recessed in which case an adapter plug is necessary.
If your appliance is dual or multi voltage, you do not need a voltage converter, only an adapter plug.