Elka Model 410 – 120-Bass 41-Key 7-Treble Switch Black Piano Accordion w/Case. Up for sale an Elka Model 410 – 120-Bass 41-Key 7-Treble Switch Black Piano Accordion w/Case! This beautiful instrument is a Used Model in Excellent Cosmetic Condition and in Perfect Playing Condition. On this one, there are some scratches, marks, few dents, tiny nicks, slight finish/plating deterioration and few other signs of wear here and there (see 15th to 24th pictures), but really nothing major. Unit comes in a Hard Case. This beautiful condition accordion has no air leak! The straps are in Excellent Condition (see 2nd, 4th, 5th and 8th pictures). The reeds are in Excellent Condition ...