Double wall stainless steel material. Introducing the Hetro Flask - your perfect companion for on-the-go hydration! Whether you're hitting the gym, exploring the great outdoors, or simply running errands, this sleek and stylish flask has got you covered. With its lightweight design and durable construction, it's easy to carry wherever you go. The Hetro Flask not only keeps your favorite beverage at the ideal temperature for hours, but its leak-proof lid also ensures a mess-free experience. Stay refreshed and energized throughout the day with the Hetro Flask!