Heat pipes have tiny holes inside and a space to contain liquids / gases. When the heat passes from the substrate to the tube, it will heat the liquid to such an extent that it evaporates and turns into gas. Then, it moves between the tubes until it is cold enough to return to the liquid state. When again liquid, it flows through the material inside the tube until it returns to the substrate and is so hot that it evaporates.
The thermostat consists of many pins usually made of aluminum. The heat coming from the tube is then spread out to allow it to fly easily. Because they are designed for a wide area, they usually do not need to be able to transfer heat like soles or pipes.
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