I was bought these as a present as I'm trying to assemble a steampunk outfit and wanted some more accessories that are universal.
They're really nice glasses! They have a plastic frame, however it's sturdy and not flimsy at all; the 'sunglasses' part of the glasses moves up and down easily and stays up, too.
Despite having two layers the glasses are easy to see through, and I feel quite happy having the glasses on the top of my head as I doubt they'll fall off easily. They even comfortably sit behind on my ears without feeling too tight or too loose.
A really nice product - would recommend!