This connector converter can convert a 7.4 x 5.0mm round shape male connector with center pin which is widely used by Dell HP laptop computer power adapters to a 5.5 x 2.1mm male connector.
The back end of this converter is a 7.4 x 5.08mm female
The male end of the converter is a 5.5 x .21mm male connector, with outside diameter 5.5mm, inside diameter 2.1mm:
can plug to a 7.4 x 5.08mm male connector, convert it to a 5.5 x 2.1mm male
connector like this:
7.4 x 5.08mm connector is widely used on Compaq, Dell and HP laptop power