Thermos

From KayakWiki

Brand name for vacuum flask.

Bottles of this type can keep a liquid hot for quite a while. Modern bottles are made of stainless steel, not glass, and are quite tough. Tea, coffee, cider or other hot drinks are great on a cool day. Watch out for hot chocolate - if the thermos cools to the right temperature, you might get chocolate yogurt.

See also: Warm drink