S'well Travelers feature Therma-S’well® Technology with triple-layered, vacuum-insulated construction designed to keep beverages colder or hotter, longer than all the rest. Made from 18/8, food-grade stainless steel with superior construction that allows for refilling and reusing easily to reduce the need for single-use plastic water bottles. Copper wall layer creates a condensation-free exterior that won't sweat on your hands or in your bag. BPA/BPS-Free and reusable. Hand-wash only.