Excelsior Accordion 80-Bass 37-Key 7-Treble Switch Black Piano Accordion w/Case. Up for sale a Excelsior Accordion 80-Bass 37-Key 7-Treble Switch Black Piano Accordion w/Case – #AE00073! This instrument is a Used Model in Good Cosmetic Condition and in Perfect Playing Condition. On this one, there are white marks (the white coating of the lower strap deteriorates) on the lower side (see 8th and 25th pictures) and there are several scratches, marks, dents, tiny notches, light waves / irregularities on the plastic frame, light finish deterioration and few other signs of wear here and there (see 1st to 8th and 15th to 25th pictures), but nothing major. Also, there are some ...