This is a Mamiya 250 mm, 1:6.3 f, double lens. It is number 43754. This lens was manufactured by Seiko, and made in Japan.
This lens is in excellent, used condition. I checked it out. I could not see any fogging. Also, there is no dust or mold on the lens, outside or inside. It comes with both lens covers. The outside body of the lens is almost scratch free. The only issue that I see is that the front, plastic lens cover is scuffed.
This lens comes in a padded case. It has been kept in this case, and you can tell, due to the great condition of the lens. The case is in rough shape. I did not take a photo of it. You will probably need to buy a new one. I will keep it in this case until sold, and will ship in it, to protect the lens..
Take a look at the photos, and if you have any questions, please e-mail.