Signal Corps Onate Ring First World War

[Markus1970]

Found a world war I signal corps ring. Very similar to the one of the treasurenet.com member DaChief:

http://forum.treasurenet.com/index.php/topic,138770.0.html

But it does not say 'sterling' on the inside marking.

Does anyone know what it is worth?

Thanks.

Markus