I was told by the owner they belonged to their grandmother and may be from the 1940s? I'm not entirely sure. I can't place what style they are, or if they're underwear or something else. The crotch is open and there are clips for garters I believe.
Spandex wasn't invented until the late 50s. The union label, from what I can see, dates them to 1963-74 I think I'd call this a panti-girdle.
I don't think I can ever get over the shock of reading a post about something someone's grandmother owned and scrolling down to a photo of something I wore as a teenager...sigh... Yup...a panty girdle from the 60's...and I suspect I still have a nearly identical one upstairs in a drawer.