What is this?

This part was bad on my '73 Swinger. If you look for OE or NOS, they want $40 and more on eBay. I couldn't justify the money for the part but wanted to make it work correctly. Through my research, I found that this particular component was used on Chrysler product into the early 90's even in Jeeps and Vipers. I finally found one for $12 from Auto Zone. I ordered it and had it the next day. System works great now! The part is Duralast 19390. I am sure other stores can cross reference to their brand but I can verify this one is right and works well.