Mir-26b 
lens for medium format camera
45 mm, 1:3.5, Pentacon Six mount, s/n 860532,  
plant "Arsenal" (Kiev, Ukraine, USSR), 1977

Sold as partly working. Lens is clean, does not have any dust or fungus. Front glass has tiny, almost invisible cleaning microscratches. Aperture and focus rings rotate properly. Aperture is always open despite of the meaning at the aperture ring. To close it, set the aperture ring at the desired meaning and then pull the pin at the rear side. Body has signs of age and use.

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

This is a wide-angle lens for medium format cameras with mount "Pentacon Six" and frame size 6x6 cm: Kiev-6c, Kiev-60, Kiev-88CM, Kiev-88C, Kiev-90, Pentacon Six and other. Lens was produced in 1970-92 at the plant "Arsenal" in Kiev, Ukraine, USSR. Lens was based on Carl Zeiss Jena Flektogon 4/50, but aperture ratio was increased.

After 1992 it was produced in small quantities under the name "Arsat".
Lens has a "jumping diaphragm" and one-layered anti-reflection coating. 
Lens official price was 350 Soviet Rubles (average salary was about 150 Rubles per month), so it was very expensive.

Lens is big and heavy, only metal and glass.
This lens can be easily used with all modern DSLR cameras. When using it on medium format it is a typical wide-angle lens; when you mount it on full-frame, it will be equal to 50-55mm, when mounted on crop it will be telelens. For example, when using on Canon crop, it will be equal to 72 mm. 

Quality of the picture is brilliant. Lens is high-contrast, very sharp and has unsignificant aberrations. Picture it true with mild colour rendering. Vignetting is absent. The only drawback is that this lens does not like contre-jour (contrast range is bad in this case). 
Offered lens has a "USSR Quality Mark" meaning that it is better than ordinary "Mir-26".

Characteristics: 
Lens s/number - 860532
Number of lenses - 8 in four groups
Frame size - 6x6 cm
Angle of view - 84o
Number of aperture blades - 6
Limit of aperturing - 1:3.5 (max), 1:22 (min)
Resolving power - (centre/edge) 48/20 lines/mm
Minimal distance of focusing - 0.5 m
Type of thread - Pentacon Six mount (P6, Exakta 66)
Type of filter thread - 82 mm x 0.75
Dimensions (mm): 96*85*85
Focal distance - 45 mm.
Mass - 582 g
One-layered anti-reflection coating