A prototype of an English concertina by Charles Wheatstone. The template for the 3D model was an instrument listed in the MET Museum:
https://www.metmuseum.org/art/collection/search/503682
Charles Wheatstone patented his concertina in 1844, but he had already been working on improvements to his prototype since December 1829 (Patent 5803, Figure 45)
This model is one of his further developments up to the first patent in 1844