A heat sink is usually made by Copper or Aluminum alloy. It is a passive heat sink that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often  use air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device's temperature at optimal levels. In computers, heat sinks are used to cool CPUs, GPUs, and some chipsets and RAM modules. Heat sinks are used with high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light emitting diodes (LED lights),  where the heat dissipation ability of the component itself is insufficient to moderate its temperature.