This is a lens from Baush & Lomb Optical Co. I acquired it about 30 years ago during a long stay in the United States and have been storing it in a dehumidified storage unit. I recently came across it while organizing. Back then, I used it for shooting with a large 4x5 camera, traveling to the locations where Ansel Adams took his photographs. Baush & Lomb is now famous for contact lenses, but it was originally an optical lens manufacturer. In the late 1800s, the Germans Baush and Lomb immigrated to Rochester, New York, in the United States and opened a lens factory. From 1892, they partnered with Carl Zeiss of Germany, and began producing full-fledged camera lenses. Carl Zeiss established a foundation in 1889, so this business partnership makes sense. Baush & Lomb-Zeiss Tessar lenses are rarely seen, and they are for large format cameras. The Rapid Rectilinear 135mm F4 lens being offered is likely for medium format cameras. Large and medium format lenses of the time, and even now, often have F5.6 or F8 apertures, with F4.5 being the brightest. As the "Rapid..." in the lens name suggests, it's a fast lens, allowing for faster shutter speeds. Back then, "Rapid..." seemed to be synonymous with lenses with bright, wide-open apertures. The lens being offered was likely manufactured between 1895 and 1905. It's a rare item from a historical perspective. The lens being offered is in very good condition. Even with a penlight, there is no dust, debris, clouding, mold, mold marks, or cleaning scratches. It appears to have been a well-cared-for lens. The aperture blades move smoothly and form a perfect circle, which is beautiful. The lens shutter is set to the T position, and it's safe to assume that speeds like 1/25th of a second won't work. The shutter and aperture mechanisms use Kodak's roll bearings. Considering that Eastman Kodak, famous for the Vest Pocket Kodak, was also located in Rochester, it seems like a logical combination for a lens. It's assembled with a Nikon F-mount helicoid and Nikon intermediate rings. By removing the front lens element (unlocking it), you can also attach the included Fujinon 150mm F5.6 large format lens. Both lenses focus to infinity (∞). However, the Fujinon lens has cleaning marks on the rear element, and the lens shutter is non-functional, so it's included as an extra. However, the aperture can be adjusted in the T position. No returns or refunds accepted.