Thanks to the unique Vacuum Isolated Copper Coating technology, the Flsk thermos bottle keeps your drinks cold for up to 24 hours and hot for up to 18 hours. A vacuum layer between the stainless steel prevents heat or cold from escaping, as it does not conduct like air. Additionally, an extra copper coating on the stainless steel helps maintain the temperature. The perfect temperature - always and everywhere. The insulated bottle combines high technical standards with perfect design, making it a highly functional and visually appealing drinking bottle. The Flsk thermos bottle is lightweight, handy, and available in three different sizes. The lid is completely leak-proof - spills are a thing of the past. Furthermore, the insulated bottle is carbonated beverage safe, taste-neutral, and completely BPA-free and environmentally sustainable. The high-quality craftsmanship from rust-resistant and taste-neutral type 304 stainless steel ensures that your new Flsk will be a long-lasting, reliable companion that you won't want to be without.