Help me identify this label on tubes


I have a 6CG7 tube that has a label on the glass that says SENCORE. 

I can’t seem to find anything on this tube. I find see tube testers called Sencore, but no tubes. 
there are no other labels on the tube. 
last_lemming
Sencore, use to be a pretty good source for test equipment. A lot of the older test equipment had valves.. Medical to space travel. Does it have an "Old" look and feel? Does it have the "Buck Rodgers" look? Loved that rocket! Tubes all over the place inside the ship.. Vacuum tubes in the vacuum of space... Will that work?

https://frank.pocnet.net/sheets/127/6/6CG7.pdf

Anyways.. Old / New? 6GC7. 6 volt, Glass, lost me after that.. C7? no Idea.. Tube historians can chime in.. That's all I got.. :-)

Regards