The dual-voltage FLEXVOLT 20V/60V MAX 9.0 Ah battery automatically changes voltage when you change tools, providing up to 6X runtime ( With DCB609 FLEXVOLT battery when used with DEWALT 20V MAX tools compared to DCB201 1.5 Ah battery pack.) in 20V MAX tools and the power of corded in 60V MAX and 120V MAX tools.