Hello! I wonder about this small box it is aprox 15 cm X 15cm with a small turning knob.

See pics.

Best Chris

Hello,
concerning RLM-List it is named "Anlasser", which means starter. It belongs certainly to radio equipment and was used (I suppose) to control tube-driven radio equipment.
Anheizen = pre-glow
Betrieb = on

Maybe some radio experts in this forum can say more about where it was used exactly (which radio equipment).

Regards,
Harald