Kodak Retina No.117 designed by Dr.August Nagel who was the founder of the Dr.Nagel-Werke in 1928, later he sold his firm to Eastman Kodak in 1932, and its name changed as Kodak AG. It was Kodak's first 35mm camera and the camera that introduced the 135 film in 35mm film cassette in 1934, still in use today.
Retina 117 and 118 were not called Retina I officially, 119 and 126 were the first Retina I.
All pre-war Retina I produced between 1936-41 with models 119, 126, 141, 143, 148, 149, 167.
Kodak Retina I No.126 produced concurrently with the Retina I No.119 "Modell I schwarz", but being distinctive by it's chrome trim "Modell I verchromt", and was offered with the Kodak Ektar lens.
But can be found with various lenses.
Between 1936-40, each model Retina I was available in two variants: Black Model I (schwarz), Chrome Model I (verchromt). Hence the types 119 and 126 are very similar, as are the 141 and 143, and the 148 and 149.
After WW2, production started again in 1945 as No.010. It was produced only for export until 1949 and the U.S. military. No.010 was almost identical to the pre-war model of the retina I No 148. First with the uncoated Retina-Xenar 50mm f/3,5 (Schneider-Kreuznach), from 1948 this lens coated, recognizable by the red triangle on it.