Keep drinks hot (65℃/149℉) for 1hour. Keep drinks cold (10℃/50℉) for 2hours. For maximum insulation efficiency, preheat or precool the tumbler prior to use by filling in a bit of hot/cold water for 1-2 mins. Do not use in a microwave or oven. Do not place near open flames. When using a dishwasher, please store them in the upper basket to avoid force and weight applied to them. Keep out of reach of children. Do not drop or subject the product to strong impact as it may cause breakage or leakage. Be careful not to pour too much beverage as it may overflow when closing. Close the lid tightly to prevent spills or leakage when carrying. Attach the silicone ring correctly. Do not hold sideways as the product is not airtight.Do not hold by the lid as the tumbler may fall and break. Some products may have thin lines on the surface due to manufacturing process. Push the lid against one side and lift to open it smoothly. Be careful when drinking hot beverage. Even if the tumbler surface is cool, the drink may still be hot. Do not leave the product under high temperature such as in a car. Do not leave the product with beverage inside for long time as it may spoil or cause rust on tumbler. Do not use the product with citrus fruit juices as it may deteriorate due to terpene contained in the fruit's skin. Immediately wash and dry well after use, then store it away from other metals to prevent rust. Do not leave it soaked as it may rust or break. Wash with care. Do not use abrasive cleansers or steel wool. Do not use chlorine bleach as it may cause rust. When rust spots are found inside the tumbler, add warm water and citric acid in ratio of 10:1, wash with soft sponge after leaving it for 2-3 hours, and rinse well.