Industar-50 red P, silver lens for rangefinder camera
50 mm, f/3.5, M39 (LTM) mount, s/n 5985873,
Krasnogorsky Mechanical Plant (KMZ), Krasnogorsk, USSR, 1959

Very good condition. Lens is clear and does not have any scratches or fungus. Inside there are microspecks of microdust. Aperture ring rotates easily. Focus ring rotates a bit not uniformly, both rings have a backlash. Body has small signs of age and use.

Camera "Zorki-4" is not included and is shown as an example of mount.

This is a standard lens for Soviet rangefinder and SLR cameras: "Zorki", "Zenit", "Crystal" instead of "Industar-22" lens. It was designed in 1953 and produced since 1953 till 1986. This lens was made in 1959 at Krasnogorsky Mechanical plant named after Zverev (KMZ), also it was produced at LZOS (Lytkarino) and KOMZ (Kazan). The lens uses the "Tessar" lens scheme. The lens is anastigmatic and antireflected. Diaphragm numbering is doubled. 

Lens had foldable and unfoldable versions, variants for SLR, rangefinder and enlarger.

This lens is very-very small and lightweight. You can easily put in your pocket, and the hardest camera will seem lighter with this lens. It is very cheap. But at the same time it has a perfect sharpness thanks to the "Tessar" scheme. Chromatic aberations are corrected. Bokeh is rather nice.

This lens is for rangefinder only, it can be mounted to SLR with M39 mount, but it will not work.

Characteristics:
Lens s/number - 5985873
Number of lenses - 4 in three groups, Tessar.
Angle of view - 45o
Number of aperture blades - 7
Limit of aperturing - 1:3.5 (max), 1:16 (min)
Resolving power - (centre/edge) 38/22 lines/mm
Minimal distance of focusing - 1 m
Type of thread - M39x1/28.8 (LSM)
Type of thread for the nozzles -  22,5 mm
Dimensions (mm): 58*58*44
Focal distance - 52,48 mm.
Mass - 102 g