The milton bliss bottle is vacuum insulated with copper coating for longer temperature retention. The vacuum insulation helps in keeping liquids hot or cold for up to 24 hours. The body of the flask is fabricated both inside and outside in 18/8 quality stainless steel. This makes it 100 percent rust-free. It is easier to drink directly from the bottle or to pour into cups and glasses without spilling, whether you are at work, home or travelling, the milton thermosteel bottle will come in handy. You can pour hot water if you use it for hot beverages and cold water for cold drinks. However, it is not suitable for carbonated drinks as they may wear out the inner body of the flask. It is multi-purpose flask to store hot or cold beverages. Cleaning instructions: Easy to clean and maintain, use a mild detergent or dish wash liquid and clean inside with a bottle brush. Do not use very rough cleaning sponges or bleaches, as they may damage the steel exterior of the bottle by leaving scratch marks. Also, keep the bottle open when not in use to avoid any odour. ※Disclaimer - "The product images shown are for illustration purposes only and may not be an exact representation of the product."