GOOQ Thinkpad Slim Power Conversion Converter Cable Adapter for Lenovo Thinkpad X1 Carbon 0B47046 Ultrabook Notebook PC (Lenovo Converter Cable) Work with Lenovo Thinkpad X1 Carbon 0B47046 Laptop Connector: one side is 7.9x5.5mm female plug, another side is Square male plug for X1 Carbon Ultrabook. Please make sure the Tip Connecter size of the AC adapter are identical to what your need before buying. Easy to carry around on travel