Double wall vacuum insulation with an additional copper plating allows for extreme temperature retention. Great for both hot and cold beverages. Keep ice cold up to 24 hours, hot for 6 hours. BPA free plastic and 18/8 stainless steel and it will never rust or leave a bad metal taste in your mouth. 18/8 stainless steel we have chosen from the most popular colors. The handle lid makes it easy to take with you or store in the bag while hiking, biking, shopping, fishing, road trips, sport events, office.