These cameras were produced by factory "KMZ" (Krasnogorsk) since 1972 up to 1978.
About 524,646 copies were made
This camera was very popular in former USSR.
Frame size 24X36mm

Main difference from Zorki-4: it has shutter lever cock

Lenses: Industar-50 (3.5/50mm), Jupiter-8 (2/50mm)
Lenses for Zorki-4K are here

Adjustable shutter speeds: 1sec, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000 of a second and "B"