Can be darlex - neoprene inside, lycra outside.
definitely some form of neoprene, ive had a few wet suits over the years that were cloth faced, some form of spandex of Lycra.
I think its just for soft furnishings use, hence the dimple pattern
quite surprised by the costs on this Etsy site... I normaly find Etsy sellers very expensive,
Yes I know they are often at the skilled craftmen/woman end of the scale rather than the sweat shop ebay/wish/Ali specials
but when a similar item can be £10 from China and Etsy want £500... thats a bit much
That said a custom made muumy bag for 130/160 Euros ... pretty good!
If I thought I could use it solo Id be tempted!
I was more surprised that seller actually from my country lol and they used to sell a bit different design ones for like 80$~ seems demand was okay and price went up in time.