Just stumbled upon these, looks like a really cool way of keeping leds cool
Oi
I think I know, where you have seen these 
-> EEV Blog
But 20$ for ONE?
That’s extremely expensive, I think.
Yeah thats where i found it, i agree it is expensive but could be handy if your driving an led hard, esp the version with the fan attached to the bottom.
I really like the idea of the on-soldered thing with a thread in it for mounting - but that module with a fan costs 30,99$ - for that money I get a lot other stuff that will do the job maybe better which can be driven harder.
With a fan, this thing will go to ~1000mA I assume - but not more than that.
Still a nice little device with a lot of potential!
I’ve tried attaching a fan to my bottom… it’s very painful…
That company is a member here, he announced those things around last spring.