PS Engineering  PMA 7000CD and PCD7100-R.  Matched set. 

Intergrated Intercom Entertainment System.

Aircraft Audio Panel, Intercom and Entertainment System with CD and other inputs.

Pilot Guide - See the PS Engineering site.

ps-engineering.com/docs/PMA7000CD

These units were just removed from my airplane when I did a panel upgrade.  They were installed in a Piper Archer and worked great.  A professional avionics shop did the removal.  NOT yellow tagged but I know they worked when removed from my airplane.

I did not use many of the advanced features.  I will give money back if the unit does not power up and does not work as an intercom / CD player.  I believe it is capable of handling an MP3 input via a separate jack (not included).  I'm not sure about this and no refunds offered due to not understanding what you are buying.  The serial numbers are in the ad.  If you have questions about what these units do please consult your local avionics installer OR call PS Engineering prior to bidding.  Thank you.