MORE: 7 Nutritionist-Approved Tricks To Drink More Water Every Day The Ozark has a sweat-free, stainless steel construction and is BPA-free. Its double-walled insulation helps hot or cold beverages maintain their temperatures for long periods of time, making it perfect for commuting, hiking, or just working at your desk all day. The shatter-proof lid can withstand dishwasher heat, so you can easily wash away germs.