20oz tumbler is with Double-Wall vacuum technology to keep drinks hot for over 6 hours and cold for around 24 hours. Made from high-quality 18/8 304 food-grade stainless steel. Lead-free and durable, rust-proof, easy to wash, and unbreakable. The advanced technology prevents heat transfer to the outer wall and is sweatproof, easy to grip, condensation free, and long-lasting. The electropolished inside delivers an elegant look. Designed for car cup holders. Extra sealed, and the lid cover provides the maximum splash-proof capability. Drinking hole on the top for easy sipping. Straw friendly. With a sweat-free design, it will always feel smooth to the touch and will keep its stylish colorful finish due to its long-lasting powder coating.