It's a USFA arm patch, not a USA arm patch, and it's exactly what it sounds like it should be. It is a little patch (about the size of a club patch) that bears either the USFA logo, or the letters USFA in various combinations of the national colors. They used to be promarily for the winners of national championship events (specifically the youth events) but they are also available for retail.
I now dangle to the left....my tassle. Get your minds out of the gutter.
"Martin was not an optimist; he was a prisoner of hope." Optimism is about assuming there's evidence that justifies your outlook while hope is about creating the evidence and procuring your own happiness or vision of the world. - Professor West