The Russian Jupiter-12 is a high quality wide-angle lens for the Leica type rangefinder cameras. It is a copy of prewar Zeiss Biogon and is regarded as one of the best Soviet made lenses, in both 39 mm LTM and Contax RF mounts.

Focal length: 35.7 mm
Aperture: 1:2.8 (settings from 2.8 to 22)
Field of coverage: 62°50'
Focusing: 1 m - Infinity
Filter size: M40.5x0.5 mm
Mount: M39x1 mm (LTM). The lens mounts and RF couples with any Leica or Leica copy (FED, Zorki, etc)

The glass is coated, the barrel has a black enamel finish

(Source: www.fedka.com)