The swit s 8u63 is a rechargeable 63wh 44ah capacity lithium ion battery that is compatible with select sony camcorders it replaces the sony bp u60 which is used with the sony camcorder pmw ex1ex1rex3f3 pmw 100200 and the latest pxw fs7 pxw x160180 it is able to exchange digital information with the camera and display the remaining power in the cameras viewfinder