Siam Silver Hallmark

[ValhallaSkies]

Curious if anyone knows what this hallmark is. I've googled for hours and can't find anything resembling it.

Thank you.

[Traintime]

Of the few threads on "Siam Sterling", this one notes the use of this nation mark beyond the 1949 re-naming to Thailand: viewtopic.php?f=29&t=35681&p=93655&hilit=siam+sterling#p93655

An additional mark for the maker (your encased "S", presently unidentified) is consistent with good practices, but not always included. Somewhat short of a true hallmark system which is well regulated.