Société La Radiotechnique "Radio Micro"

Radio Micro nickel based triode

French 'Radio Micro' valve

"Radio Micro" was a trade name of the Société La Radiotechnique, who in 1927, became Dario. This valve is a thoriated tungsten filament triode made in 1923. It bears opposite the Radio Micro trade mark an 'S' in a circle with 'HH' below.