The DeWalt 54/18V 9.0 Ah XR FLEXVOLT Battery offers unrivalled runtime and performance that gives unprecedented levels of power for heavy duty applications without the need for mains power. This power opens up new applications on a cordless platform and makes existing applications quicker. The faster application speed means that despite the higher voltage, less energy is used overall. The XR FLEXVOLT batteries are 18V batteries that switch up to 54V when placed on a XR FLEXVOLT tool. This innovation means that there can be 54V power across a whole range of tools without the inconvenience of a cable. The XR FLEXVOLT battery pack is also backwards compatible with all DeWalt 18V XR tools.