Keep a spare ThinkPad 90 W AC Adapter to hand to ensure your ThinkPad has a consistent flow of power. Keep one in the office, one at home and another in your carrying case for immediate, convenient access to power. This ThinkPad AC adapter is perfect for use as a spare or replacement adapter for compatible laptops. It is compatible with all Lenovo laptops with the rectangular "slim-tip" common power plug. It is not compatible with legacy notebook systems with the round, barrel-type power plug. ThinkPad AC adapters are compact so you can easily keep a spare tucked into your carrying case at all times. This 90 W adapter will perform to the exact same standard as the one which originally came with your laptop. It is highly energy efficient and is backed by an official Lenovo one-year warranty. System building block accessory Performs to the same specifications as the standard AC adapter that ships with the Lenovo laptops. Energy efficient with Energy Star V (ES 2.0) Compatible with Lenovo laptops with the rectangular "slim-tip" common power plug Not compatible with legacy notebook systems with the round, barrel-type power plug.