“Our stainless steel water bottles keep hot liquids hot and cold liquids cold” This is the very saying you can hear from water bottle suppliers and manufacturers, since the invention of the insulated bottles. But how? The answer is foam or vacuum packing skills. However, there is more to stainless steel water bottles than to meet the eye. One heavy-duty bottle is a bottle within a bottle. What’s the deal? There is foam or a vacuum between the two containers. Containers filled with foam keep cold liquids cold while vacuum-packed bottles maintain hot liquids hot. Since the early 1900s, this method has been used and shown highly efficient, thereby becoming popular among people who would like to drink on the go. Travelers, athletes, hikers, outdoor activity lovers, or even busy people who enjoy hot water or cold water prefer to have one and even some baby bottles are also made insulated.