The dual voltage 20/60 VDC MAX FLEXVOLT® 9 Ah battery automatically changes voltage when you change tools, providing up to 6X runtime in 20 VDC MAX tools and the power of corded in 60 VDC MAX and 120 VDC MAX tools. Take on tough jobs with this battery because patented technology and large format cells mean it runs cooler than the leading competitor 9 Ah battery pack under a constant discharge. This is the battery for FLEXVOLT® power and long run time. DeWALT® FlexVolt® Battery Pack, Premium, Bare Tool, Lithium-Ion Battery, 9 Ah Battery, 20/60 VDC Charge, For Use With: MAX 20/60/120 VDC