This is a beautifully fully restored Settimio Soprani accordian. It was originally made in Castelfidardo, Italy. These instruments were produced between 1872 and 1945. This particular instrument was made at the end of that period, around 1945.

The restoration work was done by the best I could find after searching the globe. It was done by accordionist, and accordion builder and restorer, Marco di Cagiada in his shop:

FISARMONICHE BY MARCO
Via Martiri Partigiani, 32
27049 STRADELLA

bass .34 .76 keys, 2 treble registers (musette and master) voices singing 2e3, 4 bass sounds.full tuning, original belts, original case in perfect working order.