Zeiss No: 31 787 No 079 on case, try pot and rangefinder.
This small rangefinder is a first generation EMK 04. EMK stands for (Raumbild) Entfernungsmeßgerät. It has a 40 cm base, and is lightweight. It was produced by Carl Zeiss Jena for the NVA in the 1950's.
Shortest distance is 50 m - maximum: 3000m..