The dual-voltage 20V/60V MAX* FLEXVOLT® 9.0 Ah battery automatically changes voltage when you change tools, providing up to 6X run time** in 20V MAX* tools and the power of corded in 60V MAX* and 120V MAX* tools. Take on tough jobs with this battery because patented technology and large format cells mean it runs cooler*** than the leading competitor 9.0 Ah battery pack under a constant discharge. This is the battery for FLEXVOLT® power and long run time.