MAX Output Batteries are most powerful and longest running batteries. These MAX Output 4.0 Ah batteries will provide up to 3X more runtime compared to the 1.5 Ah lithium-ion battery (AC870015). Pair MAX Output batteries with tools for maximum power in any application. The advanced electronics in MAX Output batteries enable users to power through the most demanding applications on the jobsite. These MAX Output 4.0 Ah batteries are compact and lightweight. which reduces user fatigue. As always. these MAX Output 4.0 Ah batteries are compatible with all 18V tools. of all. these batteries are eligible for the Industry Only Service Agreement. simply register within 90 days of purchase for FREE Parts. FREE Service. For LIFE. Charger sold separately.