This is a YASHICA Yasimar 80/3.5 lens, originally equipped on a Yashicaflex, with an M39 mount and an M39-M42 adapter ring. The Yashicaflex, a popular twin-lens reflex camera, began with the Yashimaflex in 1953, with a total of 25 models sold. The exterior shows some corrosion on the name ring, but the optics have been cleaned of scratches, mold, and dust, and are mostly clear. (Not a mint condition) Upon close-up inspection of the lens, some light cleaning marks are visible, but the resulting photos show little flare, so it shouldn't affect shooting. If you are concerned, please refrain from purchasing. The shutter was operational after maintenance, but the shutter lever interfered with shooting, so it was disassembled and the shutter mechanism removed. Since I took photos using the M39-M42 adapter ring as an M42 mount lens, I'll include the adapter ring as a bonus. I've heard that Tomioka Optical made this lens after the Tri-Lausar. You can easily enjoy taking classic photos with it. Thank you for your consideration.