Thermos vacuum insulation virtually eliminates temperature change by creating an airless vacuum space between two stainless steel walls. The result is an insulation layer that performs better than any other. A superior insulated container you can depend on to keep your beverages hotter, colder, fresher, longer. The Thermos Food Jar has a wide mouth that makes it easy to fill and eat out of, and keeps food cold for up to 7 hours or ot for up to 5 hours.