MAX Output Batteries are RIDGID's most powerful and longest running batteries. These RIDGID 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 RIDGID 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 RIDGID MAX Output 4.0 Ah batteries are compact and lightweight, which reduces user fatigue. As always, these RIDGID MAX Output 4.0 Ah batteries are 100% compatible with all RIDGID 18V tools. Best of all, these batteries are eligible for the Industry's Only Lifetime Service Agreement, simply register within 90 days of purchase for FREE Parts, FREE Service, For LIFE. Charger sold separately.