Backup battery (PRAM) board for the dual layer superdrive 1.67GHz model (1440x960 screen) of 15" Aluminium PowerBook G4 only. This board will not work in the earlier version of the 1.67GHz PowerBook (1280x854 screen). This board houses the rechargeable backup battery which stores settings such as the date & time. This board comes with the connector cable to connect it to the logic board.