A JSK from a German indie brand, made from 100% cotton.
Received as a gift but have never worn, since it doesn't really fit my style.

The etsy listing says the dress fits up to a 4XL or a German size 48. Size 48 is the equivalent of a UK 18 or 20.
I would say both the waist and bust can stretch to about 110 to 115cm.
Half back shirring and full waist shirring, both of which are really stretchy.

I can't find the original etsy listing for this dress anymore, but the dresses from this brand use the same dressmaking patterns, so I will link to another dress from this shop in the reference link. The info in that listing is applicable to my dress as well.
The image in the product picture is this exact dress.

Shipping within Germany: ~5 euros
Shipping within Europe: ~15 euros
Contact me for shipping quotes to other places, or if you need an exact quote.