PhotozymeMD Vacuum Insulated Reusable Water Bottle 17oz

This water bottle is made of double wall stainless steel, with vacuum insulation with copper plating helps keep drinks hot or cold for hours.

A stainless steel bottle that has been "vacuum-sealed" has two walls: one on the inside and one on the exterior. It also has a gap (insulation) layer between the two airtight layers (sealed). Collisions between molecules are used to transmit heat through conduction. A vacuum, on the other hand, is simply empty space. It is devoid of molecules or only includes a small number of them. As a result, there is no heat transfer by conduction. Heat is redirected into the hot liquid inside the container instead of escaping.

They keep heat where it's needed and wanted: in your drinks, not in your hands. 

Benefits:

• No sweat - even when filled with ice the outside remains dry
• Safe to use and easy to clean - does not absorb flavors or odors
  
• Retain temperature for hours - hot liquids stay hot; cold liquids stay cold
  
• Better for the environment - reusable bottle to prevent waste of plastic bottles