A glass-ceramic hob is a type of electric hob with a smooth and flat surface made of a special glass-ceramic material. Beneath the surface, heating coils are located, which heat up after being switched on and transfer heat directly through the hob to the bottom of the cookware. The cooking zones are clearly marked on the surface. After switching off, the active zone remains hot for some time, indicated by a 'residual heat indicator'. This type of hob is compatible with most types of cookware, with the only condition being a flat bottom to ensure good contact and efficient heat transfer. Control is usually touch-sensitive directly on the hob or by means of rotary knobs.