I have had these two remotes in my small collection for many years. I understand these are from the 1956 Zenith model year.

The more I look into the use of the red S-40466 Test Generator, the more I believe this is a fairly rare piece to have survived all these years. I believe not all dealers would have had them but I am sure that any serious Zenith TV serviceman would have had one. I have noticed Zenith used these for a few years after the 1956 models in their Space Command Service Manuals.

Also, the black "400" was obviously the consumer's remote that seem to be fairly hard to find these days.

I am curious what your thoughts are here and if any of you have these in your vintage TV collections.