These shapes are incredibly confusing as it seems a fair number of glassworks have produced similar designs.
The Alsterfors vases have hot worked rims(unlike Strom's glass).
I have three different sizes, all labelled. I also have a Ryd vase which is labelled with fire polished rim, I do recall the glass being slightly thinner and same height as Alsterfors.
Unfortunately, I'm not at home to do a side-by-side photo of them.
I do have these pics which as you can see, the spacing of the rings are slightly different, the Alsterfors ones are spaced wider apart.
It would seem that yours Adam, is probably by Ryd(but only probably!).
Sorry about these pics, they're old! I need to take new ones!
Here are some old pictures of the Alsterfors vase i have: http://www.flickr.com/photos/art-of-glass/sets/72157615369127066/
and this is the Ryd vase:http://www.flickr.com/photos/art-of-glass/sets/72157624484006438/