Grey plastic case insert for the left hand ports (dc-in, modem, USB and audio ports) of models of 15" Aluminium PowerBook G4. This item is stuck onto the inside of the bottom case and provides electrical insulation between inserted plugs/connectors and the PowerBook casing. It can be stuck in place with contact adhesive or double sided tape.
This is a used, tested & working part from a recycled Powerbook.