Russian Zodiac 30mm f/3.5 Fisheye Lens for the Kiev 60 / Pentacon 6 medium format camera (also Exacta 66). Full frame with 180 degree diagonal angle. Equivalent to a 16mm lens for a 35mm camera. You can pick up adaptors for other cameras.
The focus and diaphragm work perfectly. There's no oil on the blades and the glass is clean and totally fungus free. The lens barrel is unmarked