After WWII, Germany was barred from producing complex cipher systems of her own so licensed designs from other ountries were produced in Germany. Hell (of Kiel) made a series of machines including versions of Crypto AG’s C52 and CD57 (well-liked by the French). The STG61 is a copy of the CD57. It is designed to fit in a large pocket, in a military greatcoat, and also fits well in the hand. The operation of the device is quite simple.
Photos and copy courtesy John Alexander, G7GCK Leicester, England. E-mail: See Museum Info section.