Label says 'Special Crystal, BG, Ekeberga'.
Ekeberga was glass factory close to Kosta. Only active between 1953-56, possibly 1952.
Ekeberga produced raw glass. The Rawglass was sold to Decor Etching(Swe: Dekor-Etsing). And they made the glass ready for sale.
These are often marked D.E.K XXX on the bottom, D.E.K (Decor Etching Kosta).
1956 Dekor-Etsing bought Ekeberga and the company SEA was formed.
Now the problem is that it was several small companies around Kosta at that time and I really don't know if Ekeberga sold to other companies as well.
I hope this information is somewhat enough.
-Dan-O