Montbell Alpine Thermo Bottle 0.35LThe Alpine Thermo Bottle has been strategically engineered with an inner chamber surrounded by a very thin vacuum. Construction of this kind creates a barrier to restrict heat transfer via conduction and convection. In order to reduce radiant heat loss, the inner chamber is copper plated to reflect heat back into your tasty beverage. The injected insulation in cap has limit heat loss from the top of the bottle. In the harsh conditions of alpine