Vintage 1980s Ducks Beer Mug 12 fl oz Mallards Water Fowl Man Cave Clear Glass. I did a little research and some identified these as Libbey glass but I am not 100% sure on this. The graphics are great! There is a manufacture fault at the rim at the top of the seam line where there is an air bubble that looks like a chip and a scratch. But, it is completely smooth and neither. This is a weighed and heavy glass mug. Measurements Height: 5 1/2 inches Across Top: 3 inches x 3 inches