The Thinkpad SL Series, including the ThinkPad SL500 laptop computer, has the reliability and durability small businesses require. It has the quality the ThinkPad brand is known for, as well as services and features tailored to meet their specific needs. Like every ThinkPad, the SL Series is black to give it a serious, businesslike exterior. Its glossy finish gives it an edgier, more personalized look.