This is brand-new and high-quality product which can convert round connector to square connector. It is 7.9mm round jack (old type) to square plug end (new type) adapter pigtail. There is special IC inside for IBM Lenovo Thinkpad. It is a special power converter cable for IBM Lenovo ThinkPad Edge laptop notebook PC such as for X1 Carbon Yoga 13 or other future laptops which DC input port is square. You need make sure the AC adapter voltage and current to be same as your original one. You can connect this adapter between old type round jack to latest laptop with square DC input port. Item Name: Power Connector Output Voltage: 20V Compatible : for IBM, for Lenovo Connector: 7.9mm to 5.5mm (Round to Square) Male: Square with Pin Interface Size: 7.9mm x 5.5mm/0.31" x 0.22" (Approx.) Length: 15cm/5.91" (Approx.) Notes: Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Included: 1 x Power Connector