Yea, it's interesting to see some of the various types/qualities of construction, from different countries manufacturers.
Particularly when it is often hidden/obscured by various 'getter' silvery colour or blackness!! Or originally in a Metal Can!
I've often found that old Russian tubes were generally built much more robustly and durable!
Interesting note...
Some brands of Vacuum Tubes were still using 'older' manufacturing processes, in regards to types of or lack of variations of thoriated heaters
etc, and different types/processes of 'getter' use. This generally resulted in a 'blackened' look from the outside. They often didn't want people
to know they were still using antiquated processes, so they would spray paint the whole outer glass with Gold coloured Paint to mask it,
before printing any writing on them.
