. The ThinkPad 170 W AC Adapter is the perfect replacement or spare power supply for your ThinkPad notebook. Just plug it into an available outlet to deliver immediate power to your compatible ThinkPad laptop. ThinkPad AC adapters are compact making them highly portable perfect for busy professionals and travellers alike. They are energy efficient with an Energy Star V (ES 2.0) rating and are backed by a one-year official Lenovo warranty. They perform to the exact same specifications as the standard ThinkPad AC adapter that came with your ThinkPad laptop. This 170 W adapter is only compatible with ThinkPad laptops with rectangular slim-tip common power plugs. It is not compatible with pre-2013 ThinkPad laptops with the round barrel-type power plug.. .