4PCS Anodized Aluminium Heat Sink 40x40x20mm / 1.57"x1.57"x0.79" Heatsink Kit Sync Cooler Cooling Fins 40mm for Electronics Module Computer VRM Led Memory Chip Peltier 3D Printer Stepper Motor

they do heat sync things

used with thermal epoxy to shape to my needs

Good quality, well made.

Very well machined parts, keep stuff cool. Would buy again

Good quality manufacturing. Specs were right on and edges are clean. Not quite sufficient for peltier cooling even with a heat dissipation fan and thermal compound but likely be good enough for other light duty applications.

worked great for what i needed...got a 20percent diff

Perfect for 3d printer stepper motors!

I used these to cool a peltier chip. The contact area is nice and smooth so I was able to use a minimal amount of thermal paste. I added a fan to the fins to help circulate air. Worked out great for my project.

Well made words as expected

These have very nice thermal transfer. They seem to be of pure aluminum, because they work better than a similar shape and fin style heatsink of 40% larger area and mass. Easy to drill and machine.

WiFiルーター子機が過熱するので、貼り付けてみました。ヒートシンクが暖まっているので、効いていると思います。

Can't complain. The measurements shown in the listing are accurate down to the tenth of a millimeter and consistent across all 4 pieces. Certainly aluminum, a neodymium magnet has absolutely no effect at all on these. Like holding a magnet to a block of wood. And the electrical resistance across a block is zero on my meter or at least too low for my device to measure.

熱伝導両面テープ付き とあるが付いていなかった。 別途買う必要が出てきた。