A nice vintage 21cm Heliar in barrel. But it comes with a unique sort of primitive focusing helical. Perhaps it saw service as a projector lens?? Me not know. The helical has matching thread and can be used as intended or perhaps cut down to make a jamb nut for mounting to a lens board. Not much to look at, and the glass is imperfect. Cleaning marks etc. Not pretty. BUT in use I found it superb. As good as my other Heliars, just not pretty. So that makes it cheap. $185 + something for the mailman.