The 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. Additionally, we have injected insulation into the cap to limit heat loss from the top of the bottle. In the harsh conditions of alpine surroundings, weight and ease of use become very important. We were able to minimize weight by optimizing the thickness of the inner chamber via a process called metal spinning. This thermos is also very simple to open thanks to the use of “grippy” silicone accents and the uniquely designed hexagon shaped cap. A turn of 180 degrees is all that is required to open the bottle and begin decanting. The Alpine Thermo Bottle has been carefully crafted with many subtle design features to facilitate its use in the toughest conditions. One thing is for certain, this is a piece of gear that is truly worthy of the name “Alpine” and Montbell is proud to bring this product to mountaineers for use around the world.