AT THAT TIME, THEY DID SOME TESTS TO FIND A REPLACEMENT FOR OPAL. ULYSSES GLASS, WAS ONE OF THOSE TESTS. ONLY 2 COPIES ARE KNOW TO EXIST. IF YOU HAVE ANY QUESTIONS, PLEASE CONTACT ME. THANKS FOR CHECKING OUT MY AUCTIONS!The item "Vintage PYREX Rare HTF 503 ULYSSES GLASS EXPERIMENTAL PROTOTYPE REFRIGERATOR" is in sale since Saturday, January 5, 2019. This item is in the category "Pottery & Glass\Glass\Glassware\Pyrex". The seller is "pyrexglass1234" and is located in Monessen, Pennsylvania. This item can be shipped to United States.