Thermal grease is known by a number of names including: • CPU grease • heat paste • heat sink compound or paste • thermal compound, gel or paste • thermal interface material. It is a thermally conductive material which is usually electrically insulating which helps to dissipate heat from a device. Its main function is to ensure there is no air space between which would act as a thermal insulator. It fills in the microscopic imperfections on the heatsink and device. It is most commonly used between a CPU and a heat sink to maximise heat transfer. It is also used on other electronic components which create heat and also need a heat sink such as MOSFET transistors. There are other types of products to eliminate the air gap under a heat sink: • Thermal Adhesive • Thermal Gap Pads