Help id Ship hallmark on bracelet

[ejenie]

Hi, I've never seen this ship mark, any help with id appreciated. Links stamped with '84' possibly style number and makers mark 'BB'. Heavy bracelet not stamped 925 but tests as sterling silver. Purchased in UK with some Euro shield charms on it. Looked around the posts but couldn't find. Closest ship mark was a Cyprus mark but that was for gold. Any assistance appreciated! Thank you.

[Dad]

Hi.
Better late than never.
It's made in Russia. Time period 1882-1896. Assay marks of the Kostroma assay office.
Coat of arms of the city of Kostroma - a ship sailing along the Volga River.
Silver fineness is 84 zolotnik (875 metric )