Thermos Nissan Stainless Steel Vacuum Cups, Mugs & Tumblers 

As with all insulated beverage containers, we highly recommend pre-heating these units by filling them with hot water - or cold water, and leaving them sit for a minute or so before storing your beverage. This will greatly increase the amount of time your beverage will hold its temperature. Thermos TherMax™ vacuum insulation virtually eliminates temperature change by creating an airless vacuum space between two unbreakable stainless steel walls. The result is an insulation layer that performs better than almost all other insulation methods, excluding glass lined containers, which are for the most part, not suited for more rugged environments. Thermos TherMax™, Superior insulated containers that keep whats hot, hot, and whats cold, cold!