4PCS Copper Heat Pipe Copper Heatsink Heat Pipe Flat Heat Pipe Computer Tube 0.3x0.8x8cm Copper Sink CPU Tube Retrofit

I dont really have the tools to check how well they conduct heat, but they seem to be working as expected for me

I was given a sample of these heat pipes to review. I build hot air engines as a hobby, and I haven't yet figured out how to employ one there, but I'm certainly interested in thinking about the possibilities. In the meantime it's fun to experiment with these, even bringing near to a candle (while holding in pliers of course), and measuring an end with a non-contact digital thermometer. Or with an ice cube, and noting the difference in performance. The speed of heat transfer is remarkable. These demonstrate well why heat pipes are used in space vehicle and computer cooling. They are reasonable enough in price to experiment with. They have a small straight form factor useful for a model experiment. They appear to be pure copper, mine were not adhesive backed like a computer IC cooler, so they do need a mechanical support. Never try to hold one if you are doing a heat experiment, and stay within the temperature limits of water vapor filled heat pipe (I assume), if you are going to experiment.

Works well. I tested it for lead and it came out positive. Not a big deal if you're gonna put it in your computer as a heat sink. But if you want to play with it, especially if you're letting kids play with it or using it to cool down food, get a different brand.

Used these to better the cooling in a laptop. Used thermal adhesive and added more cooling volume to my laptop. Works great good quality heatpipes. Small but perfect size for my needs.

useless product totally fake. Not working at all

This is not a heat pipe, just flat copper plate, or a faulty heat pipe. The heat transfer rate too slow.