These cameras were produced by factory "KMZ" (Krasnogorsk) since 1972 up to 1984 and in 1988.
About 979,000 copies were made.
It has selenium light meter.
Frame size 24X36mm.
Shutter is curtain type.
Lenses: series Helios-44M
Lenses for Zenit-EM are here
Adjustable shutter speeds - 1/30, 1/60, 1/125, 1/250, 1/500 of a second and "B".
The main difference from Zenit-E: you should use the camera with automatic diaphragm lenses