Please note power and connector = 7.9 x 5.5mm with internal pin. This article is a high-quality power supply unit. It is ideally suited as a replacement or second device and supplies your LENOVO THINKPAD T420 with power in the same way as your conventional mains adapter and enables reliable charging of the battery. Note: If we do not expressly state that this is an original product, we are supplying a compatible product. This means that it is not an original product from the manufacturer and is therefore not manufactured or recommended by the manufacturer. All brand and product names belong to their respective owners and are used only to describe compatibility.