A kransen is a headpiece that unmarried women would wear. When they got married it seems like they would store their kransen for their daughter and the woman would wear flower crown on their wedding day.
Many people used kransens though. Viking women who were unmarried used kransens and unmarried women who followed paganism would also use Kransens.
It seems like most women only had one kransen and they would pass it down to their daughters for multiple generations.
From the Vikings it seems like it was made out of either leather, metal, or a combination of the two. The most common example I can find is Astrid from the show/movies How to Train Your Dragon.
There's a show, I believe it's on netflix, called Merlin in which Morgana wears a headpiece similar to a kransen. Something I read referred to Arthur as a pagan king.
Morgans wears multiple different headpieces throughout the show. That could be in an accuracy in the show though. Also Morgana is royalty so she could just have more as some sort of status symbol.
One of the things that makes it stand out is that she only wears it on major occasions. Like at a banquet and a jousting tournament.
There was another character in the same show that also wore a similar headpiece. Her name was Queen Annis and she was a recently widowed woman. If that's what she was wearing then putting it back on could've been a sign of her unmarried status / widowhood.
