Blaupunkt Heliodyn IV
DC Amplifier Triode
1928 (German)

The Ideal Co, under their trade name Blaupunkt (translates to "Blue Point"), sold tubes for a short time for use in a few receivers designed to use them. There were 3 tubes in the series, the Ampladyn, Heliodyn, and Superdyn. The tube label lists Huth-Telefunken as the actual manufacturer. The filament was rated at 3.5 volts and .06 amps, and the plate would handle 180 volts.