Heat sink is a substance used to dissipate heat between heat-generating surfaces and is commonly used in electronic products. The top of most microprocessors is not perfectly flat. Quality heatsink components are needed to maintain heat so that all components function smoothly. Some products have microscopic grooves and others may even have slight bends, creating an air gap between the microprocessor and the heat sink and reducing the cooling efficiency of the heat sink. The air gap is filled by applying a thin layer of thermal grease to the top of the microprocessor and the base of the heatsink.