The water bottle is constructed from stainless steel, with double-wall vacuum insulation that keeps both hot and cold drinks the perfect temperature for longer. It also prevents condensation from forming on the outside of the bottle, eliminating messy water rings. The leak-proof lid is easy to open, with a push-button release and a sliding lock that will keep it from unlatching accidentally. It's easy to take this 13.5-ounce bottle on the go, with a built-in carrying loop that stores against the lid when it's not needed, and a shape that fits in car cup holders. All the materials are durable, made to last, and completely BPA free. Hand washing is recommended, do not microwave.