This is brand-new and high-quality product which can convert round connector to Rectangle connetor. The rectangular end is close in size to USB A connector, and it has a signal pin in center.The barrel end is compatible to male 5.5mm (O.D.) * 2.1mm (I.D.). There is special IC inside for IBM Lenovo Thinkpad.
You need make sure the AC adapter voltage and current to be same as your original one. It is a special power converter for IBM Lenovo Notebook as below:
Package Content: Convertor Connector 28 pc Set