I did not know this.
I remember these GE bulbs back in the 1960s but never did know what the red 3 was about.
Now I know.

http://www.ebay.com/itm/1959-Press-Photo-GE-new-florescent-lamp-bulbs-in-Cleveland-Ohio-/351055299487?pt=Art_Photo_Images&hash=item51bc86c39f

3100 lumens for a 40 watt fluorescent bulb, a record high according to the May 1959 memo.

I think jercar954 will like this. He's been looking for a definite explanation of the 3 lamp for a long time, and this might be it.

I think jercar954 will like this. He's been looking for a definite explanation of the 3 lamp for a long time, and this might be it.

These type of GE bulbs were very common in the 1960s.

Now I feel that much more proud to own a pair of these.