Hi, Cyrillic 4ЛЮ (LYU) stands for the maker Leningrad Jewelry Factory (Ленинградская ювелирная фабрика). Number 4 in front of it is year code for 1974 . In 1961 the Leningrad Jewelry Factory and the Leningrad Jewelry and Watch Factory merged. The mark on the right is state control mark for silver 8...