System: Gerl (unisonoric, logical)

(Collection Oriwohl, Nr. 146)

System: Dr.med. Franz Michael Gerl (Hindelang in Bavaria), Patent dated 6 Dec. 1891

Single-tone harmonica (i.e. without chord keys as on the accordion). Both manuals are constructed identically (same fingering pattern), but with opposing tone direction and the resulting different fingerings.

The instrument type seems to be the first single-tone model after the English concertina, which is unisonoric on both sides and has a consistently logical keyboard system.