Here they are on an overview.
https://www.flickr.com/photos/advance-design_parts_co/8258511484/in/album-72157632208362076/
A caution on buying a used Air-Flow set-up make sure you get all the parts, there is a lot to a correct installation.
https://www.flickr.com/photos/advance-design_parts_co/44267047400/in/album-72157631868452754/
Correct heaters for a ‘49 will have the aluminum plaque, there are slots in the heater body for it.
https://www.flickr.com/photos/advance-design_parts_co/8129304429/in/album-72157631868452754/