I do believe that the "Ss" it's that it is 92.5 % silver
"925" or "SS" represents certified "sterling silver" and is stamped on jewellery to demonstrate the high quality of the product.
This stamp represents the fact that the piece of jewellery you are buying consists of 92.5% genuine silver. The other 7.5% will be alloy to help prevent tarnishing. Typically copper is used, although zinc, platinum or geranium are also common./ Per Ebay resources
The marking is an Edinburgh silver company
S.S. is stainless steel, SS is sterling
Please feel free to ask any more questions. Thank you for looking.