This is a lovely old sterling silver medal.  It is in the shape of a shield and has STS on the back.  I am unsure of the age.

I have not polished it for you, I think it brings out the charm leaving it a little tarnished.

It comes on a gold pin.  The medal measures 4cm x 3cm.  These medals look wonderful worn as a pendant, brooch or on a charm bracelet.