Double-wall vacuum-insulated walls keep beverages icy cold or piping hot for hours. Lightweight 18/8 food-grade stainless steel that is non-leaching and will not retain taste or odor. Designed to fit in your backpack and most car cup holders with its narrow bottle design. Includes a standard mouth leak-proof straw cap. The silicone ring ensures a snug fit to the top of the bottle to retain your beverages' temperature and is easily removable for proper cleaning. The lid is made to screw off and on your bottle easily.