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					Originally Posted by RHClarke  What is it for?  Here is a photo of the "S" stamped just forward of the two forward knee action shocks - the circle (a pencil outline to make it stand out) got sandblasted away: | 
	
  The circle with the "S" inside is the trademark of A.O. Smith Ltd. This company has stamped frames for the automotive industry for many years.
 Here is some history,
      
http://www.aosmith.com/About/Detail.aspx?id=130
Paul