FrostyTech has posted a review on the HHC-001 Copper Heatpipe Heatsink

The two copper tubes which jump out of the Coolermaster HHC-001 and then swing around back in are hollow and encapsulate a vacuum. Around the inside of the copper tubes is sintered copper which acts like a wick for a small amount of working fluid (usually water) which is also contained in the tubes. When one end of the heatpipe gets hot, say from a nice little processor, that small amount of water vaporizes in the vacuum atmostphere inside the copper tubes. As the vapor makes its way to the other end of the copper tube it cools down and begins to condense. With no place to go but back, the condensed water vapour travels along the wick structure (coating the inside of the tube remember) back to the heat source where the entire process is repeated again, and again.

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