Help identify hallmark found on side of the street

[drmai]

ISorry for the low quality images.

I found this on the side of the road in San Francisco! It is not magnetic (very very slight attraction) and I figure it is probably silver. Any ideas as to the identifdication of this hallmark?

Thanks!

[dognose]

Hi,

Welcome to the Forum.

It's not a hallmark, but a maker's mark only. The use of the 'crossed keys' mark was used by several platers worldwide.

Trev.