This egg shaped cup with a AS lid is made of T304 stainless steel inner and T201 exterior. Double-walled, copper lining and vacuum insulation keeps the exterior from getting hot or sweating when it's holding beverages of any temperature, and clear push-seal lid lets you see inside the tumbler when you're not sure how much or your drink is left! It's a great gift for employees, new clients, tradeshow guests and much more!