Calumet sold lenses from various manufacturers under the "Caltar" house name over the years. The Caltar Pro is the Calumet-branded version of Schneider's single-coated Xenar.
This 300mm Caltar Pro is a Tessar design with a 347mm image circle, providing modest movements on 8x10. The glass is clean and clear and the Copal 3 shutter sounds appropriate on all speeds (the apparent mark in the fourth picture is actually on the heat-pad surface, not on the glass). It takes 67mm filters and comes with a non-original Rodenstock front cap and a Caltar rear cap, as well as the retaining and spacer rings. There are the usual minor signs of use on the lens barrels and shutter - little nicks and scuffs - but nothing that will affect usability of image quality. This is a very nice lens that is simply heavier than I want to carry, especially after my recent medical issues, and I never even mounted it on a lensboard as it was really overkill for 4x5.
My asking price of $345 includes insured US shipping and PayPal G&S fees and shipped to your PayPal-verified address. International buyers - contact me to talk about shipping options. I will not understate the lens' value on customs forms.