These used taillight mounting washers are sold individually for your Mercury Cougar. Two different inside diameters on these, we have them mixed, because they are in such short supply. Normally installed with a dollop of black goo for sealing out moisture.
*NOTE* Need help diagnosing a Cougar turn signal problem? Victor Yarberry is the world's most knowledgeable expert on the subject. Vic has owned Cougars since the 1970's and is the designer of all of our solid state sequential systems. There is no question he cannot answer! Here is a link to a great source of information on the subject.