I have a similar one with three flattened sides, which I think yours is, but uncased, and believe it to be Elme Glasbruk, Sweden.
But also have several more variations on a theme bottle vases which I attribute to Elme also, i.e. melon shape cased & uncased, or pushed in on one side or flattened on two sides.
All are the same height - 9½" (24cm).