Fitian Rectangular Round Tip Spare 20v Power Adapters Converter Cable for Lenovo Thinkpad X1 Carbon 0b47046 Ultrabook Notebook Pc This product cannot work for Lenovo ThinkPad T440P, T540P Feature:a 5V 1A USB Port for Charging USB powered devices. 23cm for the cable specially designed for Lenovo ThinkPad X1Carbon Input Port(female): outer diameter of 7.9mm, diameter 5.5mm; Output Port(male): Square mouth Compact and lightweight Design ,Convenient for travelers and business users.