Changed my oil the other day and noticed this piece of metal just freely hanging out right in front of the cat. Assuming it HAS to be from either the flex pipe (nothing seemed damaged) or from the header connection. I broke my hand so couldn't get under to get a better view at the header. The 'ring' was a solid piece all around (no slit) , it easily cut with tin snips. Haven't noticed any exhaust leak (smell or sound) or pending codes.