316 Stainless Steel Interior with Ceramic Coating: Durable and rust-resistant, providing an excellent, long-lasting thermal performance. Three Convenient Sizes: Available in 350ml (15*7.2 cm), 500ml (19*7.2 cm), and 750ml (26*7.2 cm) – perfect for different needs and preferences. 12-Hour Heat Retention: Keeps your beverages hot or cold for up to 12 hours, ideal for travel, work, or daily use. Leak-Proof Design: Secure screw-on lid ensures no spills, making it safe to carry in bags or backpacks. Portable & Stylish: Compact and sleek design, easy to carry and fits in most cup holders.