20oz tumbler is with Double-Wall vacuum technology to keep drinks hot and cold for hours. The tumbler is made from high-quality 18/8 304 food-grade stainless steel. Lead-free and durable. Rust-proof, easy wash and unbreakable. Sweat proof, easy grip, the advanced technology prevents heat transfer to outer wall, condensation free and long lasting. Electro polished inside delivers elegant look. Designed for car cup holders. Extra sealed and the lid cover provide maximum splash-proof capability. Drink hole on the top for easy sipping.