30 oz. Stainless Steel Polar Camel Tumblers features double wall vacuum insulation with a clear lid. The mug has a narrower bottom to fit most standard cup holders. It is 2X heat & cold resistant compared to a normal tumblers. Polar Camels are made from 18/8 guage stainless steel (18 percent chromium/8 percent nickel) – also known as Type 304 Food Grade.