The company from Eckernförde originally has started under the name "Tauchtechnik Grütter" as
importer of products from "La Spirotechnique".
Tauchtechnik (German for "Diving Technology") was a former diving equipment manufacturer
trading, in the 60s, at Niewark 10, 233 Eckernförde, a German town in Schleswig-Holstein on the coast of the Baltic Sea approximately 30 km northwest of Kiel.
Their products included single hose regulators and double hose regulators,
which were also offered by Barakuda.
Tauchtechnik has manufactured the singe stages double hose regulators Passat
and Passat II.
Tauchtechnik Passat I - Picture
1: Frank Werthwein
Pictures 2 and 3: http://www.seveke.de/tauchen/altes/herst-kompakt/tauchtechnik
Probably, they have had the Swiss regulator "Colombomatic" as a model. Initially, they have installed Colombo's mouthpiece in their regulators and, later, Tauchtechnik manufactured their own mouthpiece.
They look almost identical.
The label of the double hose regulator Passat I is yellow and
black, the Passat's II label is Blue and Gold and the Passat's V
label is black and gold.
1. Tauchgeschichte Spezial
5/2015, Kapitel 11
2. Tauchtechnik Catalog