Product details:

The 18V LXT Adapter adapts the LXT Portable Backpack (PDC01, sold separately) for use with 18V LXT products allowing longer run time. The PDC01 is a portable power supply unit, a backpack that holds four lithium-ion batteries to provide longer run time when used with 18V LXT products. The 18V LXT Adapter installs quickly and easily for added user convenience. It is made of high-quality materials for durable construction and long life.