Jupiter-12 red P, 
silver lens for rangefinder camera
35 mm, f/2.8, Contax (Kiev) mount, s/n 6004589, 
Krasnogorsky Mechanical Plant, Krasnogorsk, USSR, 1960

Very good condition. Lens is clear and clean, does not have any fungus. Front glass has small tiny cleaning microscratches. Inside there are microspecks of microdust. Aperture ring rotates properly. Focus ring rotates tightly. Body has small signs of age.

Camera "Kiev" is not included and shown as an example of mount.

This is the copy of "Carl Zeiss Jena Biogon" 2.8/35. Firstly was called "BK-35" (Biogon from Krasnogorsk, 35mm). It was made at three plants: KMZ (Krasnogorsk), Arsenal (Kiev) and LZOS (Lytkarino). In 1947-1952 lenses were made with lensblocks from Western Germany. In 1952 KMZ started to make it own lenses entirely.

Lenses were made with two mounts: Contax (for "Kiev" rangefinder) and M39 Leica screw mount (for "Zorki" rangefinder). Had two colours of body: silver and black. Silver lenses are better for black-and-white film and black lenses are better for colour film.
Lens is wide-angle and has one-layered multi-coating.

Offered lens was produced in 1960 at KMZ (not LZOS or "Arsenal"), is early type.

Characteristics: 
Lens s/number - 6004589
Number of lenses - 6 in four groups
Angle of view - 62o50' 
Number of aperture blades - 5
Limit of aperturing - 1:2.8 (max), 1:22 (min)
Resolving power - (centre/edge) 34/12 lines/mm
Minimal distance of focusing - 1 m
Type of thread - Contax RF mount
Type of filter thread - 40.5x0.5 mm
Dimensions (mm): 57*57*58
Focal distance - 35,75 mm.
Mass - 118 g
One-layered anti-reflection coating