In 1930 Hohner presented a new “Chromonica”. It included an internal spring which was another leap in harmonica engineering.
The patent #DE490 654 was submitted in 1927 and granted to Hohner in 1930.
Additionally, Hohner came out with a three and four octave version of the Chromonica.
Hohner added also a separate Larry Adler line (junior 10 hole and 12 hole version) with enamel cover plates. Later on, a four octave model was added.
The “Chromonica” design has been copied by various other harmonica manufacturers.
Below a selection of some of the copies: