18cm 6.8 Ernemann Doppel Anastigmat lens

I have placed an 18cm 6.8 Ernemann Doppel Anastigmat lens in Cronos shutter on the classified page. Maybe I should have asked a question about it on this forum first. I listed it as best offer because I really have no idea of the value of the lens. If anyone has any knowledge about the lens and would like to weigh in on any aspect of the lens, any aspect of it's performance, or value, please feel free to make any comments.
Thanks,
Doug Webb

It's a four elements in four groups kind of anastigmat, but that's about all I know about it. Since the focal length is given in cm, I would assume it dates from the 1920s or 30s - and the Ernemann Cronos shutter was patented in 1925. Unless you've made a typo - the "Chronos" shutter can be older.