Introducing the 4-Pack 12oz. Elk and Friends Eco Kids Glass Silicon Tumblers w/ Straws and Lids. This set of drinking glasses is perfect for kids and adults alike. The tumblers are made of durable glass and silicone materials and have a capacity of 12 oz. Ideal for cold beverages, the set comes with straws and lids for spill-free drinking. Use them at home or on-the-go, and enjoy your favorite drinks while being eco-friendly.