Back when Corelle was new,the Corning Glass Works included this little postcard with every purchase. Returning this card allowed the buyer to get a replacement piece if there was a problem.  It's interesting to see that there were only 5 patterns listed and the damage categories were few. Now that Corningware, Corelle and Pyrex are huge, this little card is a curious reminder of their origins, The card is marked 4/72.