I work for an engineering firm and we are cleaning out our old lab. We have this YSI 57 oxygen meter that hasn't been used in some time. I don't know much about it so I wasn't able to test it very well. But it does calibrate to zero and red line. Other than that, I checked the temperature and compaired the readings to a probe that I know works and they were about the same. As for as the oxygen readings, I don't know enough about the instrument to test that.
If you have any questions, please feel free to contact me. Thanks for looking!