The double-wall vacuum-insulated walls give you a worry-free mind knowing your beverages are kept icy cold or piping hot for hours. Made of lightweight 18/8 food-grade stainless steel that is non-leaching and will not retain taste or odor. The double-wall technology prevents condensation on the outside for those hot sunny days while keeping the heat within the inner wall so you don't have to worry about burning your hand on your favorite hot beverage. The 20oz size is ideal to use as your everyday coffee cup and designed to fit comfortably in your hand and most car cup holders. The vacuum-insulated walls ensure when you fill it with your favorite piping hot morning coffee, or tea, it will last until your next refill. The double-wall technology prevents sweating on the outside of the bottle, so you don't have to worry about water rings on your desk.