Vacuum Insulated Stainless Steel Commuter Backpack Bottle TherMax double wall vacuum insulation locks in temperature to preserve flavor and freshness. Unbreakable 18/8 stainless steel interior and exterior withstand the demands of everyday use. Drink lid opens with push button ease and locks closed for leak-proof travel. Light and compact design for effortless transport and storage. Bottle stays cool to the touch with hot liquids and is condensation-free with cold. Contoured body is comfortable to hold and fits most automobile drink holders.