Insulated Food Thermos BEST VACUUM INSULATION TECHNOLOGY (WITH COPPER LINING): How do you improve upon a Double-Walled, Vacuum Insulated Food Thermos? Simple. Add an Interior Copper Lining. This advanced design technology helps improves the Thermal Insulation in our Bklyn Bento Food Jars. Keeping your hot food and beverages hotter longer… while keeping your cold food and beverages icy cold for hours. SAY AHHH...(WITH A NICE WIDE MOUTH): We designed our Food Jar with a Wide Mouth. This makes it easy to fill, eat, and clean. DON'T SWEAT THE SMALL STUFF: Our Copper Lined, Double-Walled lunch box will not transfer heat or cold to the outer walls. That means your Bklyn Bento thermos never feels hot or cold while holding in your hands. This also means “No Condensation” or “Sweat” will build up on this food container; keeping the inside of your travel bag nice and dry. 100% LEAK-PROOF: Perfect for those homemade Soups, Stews, Mac & Cheese (yum), Iced or Hot Coffee… you get the idea.