This little clear glass insulator is embossed with the Cyrillic letters ШЛНС-2 which are equivalent to Sh L N S - 2 over 1961. Base diameter 2 3/4 ", and 3 1/8 inch tall. CD unknown at this time.

[id=99129832; Close up of embossing]

This may actually be a CD 541.5 [id=293824615; compare with these two]] including a milk-white glass one!

[IFONA CD ??? sim 459]