This is an interesting lens, a Fujinon 50mm 1.4, this is not the SBC version. It has the yellowing glass that some fast lenses of it's era show, radioactive element? I don't know, but I've read that it could be. UV exposure can clear it up. This particular example has some interior haze that is rather serious, I think it shows in the picture.
I don't know if that can be cleaned out or not, so it is priced accordingly. This is an M42 Pentax / Practica thread mount lens.
PM me with questions or offers.