Please identify these NOS 6550s

https://forum.audiogon.com/discussions/[URL=http://img4.imagetitan.com/img.php?image=23_ge2.jpg][IMG]http://img4.imagetitan.com/img4/small/23/23_ge2.jpg[/IMG][/URL]

any ideas on this brand? Matched to 155/14/12 155/14/12 155/13/12 155/13/12

only have one of this
http://img4.imagetitan.com/img.php?image=23_ge1.jpg
and two that show white fog
http://img4.imagetitan.com/img4/small/23/23_ge2.jpg

any idea on if/how a complete quad can be assembled? Any use in the "good" one, assume the fogged ones goners? Measure it and ask the usual outlet for a "match"?

Obviously one of those tubes is a GE that's the brand. I am not sure on the other tube. If you're trying to assemble a matched quad you need to get them tested and see how closely their parameters match.

I believe the logo on the first one is  Shuguang. Because they are at least 20 years old I wonder how they compare to a current batch?