I bought many of these cheaply in a box two decades ago - good glasses for a party though I didn't have too many parties to justify them of late, so I took most of them to the charity shop to clear space.
Thing is, the sheer lightness of them make the small one good for my elderly Dad to use, and naturally he broke one and we only have one left.
I hope the picture conveys what I mean - they just don't seem like normal fairly heavy glass, and they're not expensive, almost the same material you might get in a glass beaker in a chemistry lab. Does anyone happen to know?