High-quality stainless steel The inner liner and outer shell are made of 304 or 316L food-grade stainless steel, which is corrosion-resistant, rust-resistant, ensures safe drinking water without odour, and is suitable for long-term use. Functional features Long-lasting heat preservation and cold preservation Double-layer vacuum insulation technology, heat preservation up to 6-12 hours, cold preservation effect is also excellent, suitable for all seasons. Some styles support 24 hours long heat preservation. Portable and practical design Lightweight cup with non-slip handle or carrying strap (optional on some models), easy to hold in one hand or carry around. The spout is designed to fit the lips for smooth drinking without spilling; some models come with a dual straw spout or straight spout. Leak-proof seal Silicone seal + leak-proof lock design, 360 shake does not leak, can be put into the backpack or car use. Details and Craftsmanship Safe Material Lid, straw and other accessories are made of food-grade PP or silicone, BPA-free, healthy and environmentally friendly.The surface of the inner liner is smooth, easy to clean, and not easy to residual odour. Application Scenario Outdoor sports: hiking, mountaineering, cycling to replenish water. Office study: alternative disposable water cups, environmental protection and health. Travelling: drinking hot water or cold drinks on the plane or train at any time. Parent-child use: children's models can choose a small capacity version, safe materials to make parents more assured.