No: N 8901020
This is a porro prism monocular with changeable objectives. It was made 1989 in the USSR by "Zagorsk Optical and Mechanical Plant" (ZOMZ) and has the Cyrillic trademark "MP" (МП – pronounce: MP). The eye caps are marked "3OM3" (ЗОМЗ) for ZOMZ.
The objectives are fixed to the body by means of a bayonet mount. They achieve either a 12 times or a 20 times magnification with a objective lens diameter of 40mm or 60mm.
The monocular body weighs 356, the smaller 12x40 objective weighs 101g, and the longer 20x60 objective lens weighs 341g. There is a glass pane at the objective end near the bayonet mount to prevent dust etc. from harming the inner prism system.
The monocular body is 140mm laong, and 63x63mm borad. With the 12x40 lens attached it is 15cm long, and with the 20x60 lens attached it is 25cm.
The lenses are ruby coated. The dioptre adjustment ranges between plus/minus 5 according to the enclosed manual.
Description by Ulrich Zeun (www.monocular.info)