Edit: Been informed that: "Hi, just FYI, this is a spring back, not Graflok. It’s pretty common to find the mix up where they replaced the back & put the old one in the Graflok box."
This is a spring back film holder for the graphlex system. It's 4x5. It seems fine. But I'll admit, I've never gone beyond medium format, so I could be missing something. I can't quite find this same thing out there, so I'm not sure what I'm dealing with. I'm going to presume it's worth more than $30, so I'll start the auction there.