Wood- and coal-burning cookstoves had cast iron stovetops with several circular openings seven or eight inches in diameter that were covered with removable cast iron lids. Cooking utensils were set over the holes and, when a lid was removed, the utensil was directly over the fire. To give some temperature control, at least one lid was generally made up of a graduated nest of two or three concentric, flat cast iron rings so that the size of the hole open to the firebox could be adjusted by choosing the number of rings removed.