A tealight, or nightlight, is a canle used in tea or food warmers or (because they last for many hours) as a night light. It is different from a regular candle in that it is encased in a thin metal cover and liquefies completely while lit. Tealights are often used to heat fondue and as food warmers. They are also suitable for accent lighting and for heating scented oil. In tealights the wick is tethered to a piece of metal to stop it from floating to the top of the molten wax and burning before the wax does. Generally, tea lights give off very poor light unless grouped together with many other tea lights; they were designed to be a long-lasting comfort light rather than a working or reading light. Tealights may be distinguished from Nightlights by the duration of burning; a tealight usually burns for 4 to 5 hours but a nightlight, which is larger, is intended to burn for a whole night (about 8 to 10 hours).