This Voigtlander & Sohn Braunschweig rare brass 45 grade Diagonal Prism, N7 serial 75783, for taking pictures with large format cameras 1870 is very rare. These prisms were produced to be placed in front of the lenses to photograph at 45 degrees without pointing the camera directly at the subject and for not being seen. It is in great cosmetic and working condition. The diameter of the mount to put the lenses is 10.5cm and the measures of the prism are 12.5x12.5cm and on the diagonal it is 18cm. The glasses are clean and clear with no haze, no fungus, no scratches, no detachment between the lenses, no fog. Some minor internal dust, that will not affect image quality. It's made all in heavy brass and the weight is over 5kg. Keep in mind to calculate the shipment cost. Perfect addition to your large format kit!