Friend or Foe Identity Transponder

The Friend or Foe Identity Transponder (FFIT) was a sensor installed by Corellian smuggler Han Solo onto the YT-1300f light freighter Millennium Falcon in order to make his ship appear friendly to hostile vessels' sensors.

Text and facts from the “Friend or Foe Identity Transponder” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.