Vintage depth gauge

[greenwich79]

Hello,

i recently got this vintage depth gauge apparently produced by Asahiseiki Co.:

I can't find any information online about it.
Does anyone know when it was produced and what is the type of luminous paint on the dial (radium/tritium/promethium)?
Also, is it worth anything?

Thanks

 

[Sam Miller III]

Marketed only in Europe
Minimum Value as a collectabe
sdm