www.925-1000.com

This piece is a sterling wine coaster with wooden insert. The piece is marked STERLING with a hallmark that may, or may not, be SWW, and 1-1/2.

The hallmark appears to be an elongate "S" over two "W"s. There is a small round ball at the bottom of the "S" which lands between the bottom of the first "W".

Thank you for any assistance with this unique mark!
Cheers!

Hi - welcome to the forums.

Your image is a bit unclear for me, but feel pretty sure it's the trademark Wilcox Silver Plate Co. (International Silver) used on their sterling goods- the clip below is from a 1904 trade publication.

~Cheryl