The heating element is brought close to the top of the battery.
The heating element must be fastened to the mug with a clamp.
Conduction occurs when you set a pan containing food right on a heating element.
Convection warms food in pans that are not actually touching the heating element.
He remembered he hadn't turned on either the heating element or interphone system.
The bottoms of these mugs have a flange which makes a recessed part and in this the heating element is placed.