NFL “Pittsburgh Steelers” 20 oz. Glass Yellow/Black Insulated Tumbler (LTT122-2) by Duck House®. Quantity: 2 Pieces. These beautiful new all-purpose tumblers have the look and feel of glass but are made of shatter-proof acrylic. Designed for everyday use around home and office, these tumblers are also perfect for parties and celebrations and make fabulous gifts for fans of all ages!