X-Rite 410TR Transmission Reflection Densitometer XRite

  
Seems to calibrate fine and the unit seems to give accurate readings. The calibration chart is incredibly hard to find and expensive when you do find one, and rare to be included with the densitometer, compared to similar listings in this price range.

Priced with that in mind. Original manuals included (2 copies). Although labeled as a transmission/reflection densitometer, you need an external reflection accessory to use that function probably available on the used market as well. This is an old piece of photographic equipment and as such the sensors and electronics may not be as reliable as they once were.