Makita LXT® is the largest cordless tool system in the world, powered by 18V Lithium-Ion slide-style batteries. The Rapid Optimum Charger is at the heart of the Makita 18V LXT® System. It provides key advantages for users of Makita 18V Lithium-Ion cordless tools. During the charging process, the exclusive built-in fan cools the battery (sold separately) by forcing air through the battery's air vents, resulting in faster charging times. The charger actively controls current, voltage, and temperature by communicating with the battery's built-in chip throughout the charging process, optimizing battery life. As a result, the battery spends more time working and less time sitting on the charger, resulting in category-leading battery charge times. (Note: This charger can also charge 14.4V Lithium-Ion batteries.)