We have always considered and collected these commercial masks and helmets as industries tribal art. Examples can be elegant in their simplicity or bazaar and complex. They are always unique, suprising and filled with personality.
Atwater Kent Model 9
The Model 9 was introduced shortly after the Model 5 in 1923, returning to a single stage of RF amplification, but with a second variometer. Comes with rare rainbow tipped tubes... $1600