A battery built for longer days. The DCB549 XR FLEXVOLT 15Ah battery provides the highest capacity of any battery on the DEWALT cordless system. It changes voltage when going from 54V XR FLEXVOLT to 18V XR tools and is compatible with almost all of your 18V XR tools and chargers. In XR FLEXVOLT tools it will deliver class leading 54V cordless power and in 18V XR tools it will provide unparalleled runtime.