This is a ballast/transformer used on Douglas aircraft and possibly other types as well. This one was removed from N834F during tear down and has been in storage since. It is in good condition without damage to the housing or mounts. The connector is also undamaged and the data tag reads ELECTRONIKA, TRANSFORMER-BALLAST ASSEMBLY, PART NO. BA170-21. Unfortunately It is not tagged and I have no way to test it so it is being listed AS IS. Thank you for looking and please see our many other aviation sales.