Contour Enthusiasts Group Archives Forums Modifications Audio New HU - what does this do?

I just got a new Pioneer DEH-P7800MP, and the wiring harness that came with it has a small box inline with the +12V constant power line. I was wondering what it was so I opened it up, there is what looks like a small transformer inside:



Any idea what this does? Some kind of filter perhaps?

My guess it is for the security system.

Detachable Face Security: This unit features a motorized "flap-face" front panel with Detachable Face Security. If the front panel is not detached from the head unit within five seconds of turning off the ignition, a warning tone will sound, and the face will fold down. The warning tone can be turned off in the menu, if desired. A face-fixing screw is supplied for making the face non-detachable, if desired. A hard plastic face case is included with this unit.

but like i said...just a guess.