The dual-voltage 20V/60V Max* Flexvolt® 9.0 Ah battery automatically changes voltage when you change tools, providing up to 6X runtime** 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.