Zenith-Single Button Remote ?

[Oldstuff78]

While scouting around eBay I came across this auction for a single button Space Command remote. Not having the privilege of owning a 60's Zenith Roundie Space Command and not seeing one in person, I'm not that knowledgeable in all the different remotes. I know there was 300, 400, and 600, but this is a new one on me. Was it the 100 ? What did the 1 button function, On & Off ?

What year was this remote produced ? 1950's ?

http://cgi.ebay.com/Vintage-Zenith-S...3A3%7C294%3A50