http://www.power-ac-adaptor.com/asus-65w-bu400aw3161g-ultrabook-ac-power-adapter-charger-p-1705.html
ASUS 65W BU400A-W3161G Ultrabook AC Power Adapter Charger

Item Specification

100% Original Genuine OEM ASUS 65W AC Power Adapter .

INPUT: 100-240V-nbsp;50-60Hz (for worldwide use)

OUTPUT: 19.5V 3.42A, 65W

Connecter size: 4.5 mm3.0 mm,-nbsp;with pin inside(ref to the picture).