So, cheap! And I prefer these to the traditional type. I can vouch for these, they are tried and tested. Though, I no longer play this big "monster" accordion, or any accordion...I do play the English concertina.
These straps are made with inexpensive regular yarn. There's stuffing -- regular craft-type fiberfill -- in every other section, the alternating similar wide sections being left empty and not sewn shut. I did find that it helped to use some short, strong dog collars at the top connection and connect my homemade straps to those.
This is a 180 bass accordion. A Pancordion Video. There's a spot for an audio pickup, but I removed the old pickup. This accordion is in....fair/good condition. I'll take no less than $500. for it, and I can always use the reeds anyway, for my foot bass...so it's good for parts. I won't ship it anywhere! Buyer has to pick it up.
There is a case, too, not sure what shape it's in.