A power adapter for home, one for the office, and one for the bag: this way, you are always on the safe side. It simply needs to be plugged into a power outlet, and the compatible ThinkPad laptop will be powered and the battery charged. ThinkPad power adapters are compact and energy-efficient. This adapter has the same performance specifications as the standard adapter included with ThinkPad laptops, so you always have a spare adapter on hand. The ThinkPad 135W power adapter is only compatible with ThinkPad laptops that feature the common rectangular Slim Tip connector. It cannot be used with ThinkPad laptops that have a round power connector.