This is a vintage Wollensak 2 inch (50mm) f/1.9 Cine Raptar C-Mount Lens for Bolex and other 16mm Cameras. It has scratches on the hood but otherwise it`s in very nice shape. The lens glass is clear with no fog and the aperture and focus work smoothly. The very edge of middle glass has small chip that (pictured) that should not affect image. Most 2 inch Raptars are at 1.5, have not seen the 1.9 listed before.
