DC Power Connector Converter CNT-X75.
This connector one end is a 7.4 x 5.08mm female jack, another end is a 5.5x2.5mm male connector. It can change a 7.4 x 5.08mm male connector with center pin (Outside Diameter 7.4mm, Inside Diameter 5.08mm) to a 5.5x2.5mm male connector (Outside Diameter 5.5mm, Inside Diameter 2.5mm).
7.4 x 5.08mm connector is widely used as Dell and HP/Compaq laptop power adapter connector.
One end: 7.4 x 5.08mm female jack
Another end: 5.5 x 2.5mm male barrel connector
Middle cable: 16AWG wires
Total length (from end to end) : around 190mm ( or 7.5")
Note: This converter female side will only accept round shape connector. You can not use this converter if your power adapter connector is not round shape. Some Dell power adapters have octagon shape connectors, which will not fit the female side of this converter. The female jack can plug into a Dell or HP power adapter with 7.4mm/5.08mm male round shape connector like this: