A double boiler looks like two saucepots, one inside the other. Food
in the upper pot is heated by the boiling water in the pot below.
A saucepan is a metal container of moderate depth, usually having a
long handle and a tight cover. They are great for stewing, boiling and
Sauciers are very similar to saucepans but tend to be shorter and wider
for easier stirring and whisking of sauces.
Butter warmers usually have much larger proportioned rims in relation
to the bottom of the pan than a sauté or paella pan would have. Butter
warmers are typically no bigger than 1.5 quarts.