iBELL Vacuum Flask are made of high quality stainless steel.Unlike plastic water bottles or single wall stainless bottles, iBELL Flask will keep your beverage of choice at your preferred temperature for hours, whether you choose hot, cold or room temperature liquids. All iBELL products are double wall vacuum insulated. They are designed to be lightweight, making them great for long hikes, days on the beach, golf, long road trips or everyday office use. Even when filled with ice, the exterior of your iBELL will never leave a puddle on your desk, drip on your shirt, or sweat in your bag.