Double wall vacuum insulation keeps filled ice cold for up to 24 hours, or boiled water hot up to 12 hours. The innovative tech applies an inner copper lining that prevents the bottle from sweating. Fill up your bottle with your favorite cold beverage and keep it refresh all day.This durable bottle is made of high-grade 18/8 stainless steel which will not be rusted or broken. Whether you are on a fun adventure exploring the great outdoors or at work, the thermos which will not retain or transfer flavors always keep the fills natural and clean taste.