that is massively overpriced, you can pick rheostats up at any electronics store for $3-$4 ... just like the one on the picture, you just have to wire it up.
the more you slow down the fan, the hotter the rheostat gets, at full fan power the rheostat does not get hot at all.
I use a 5W/100ohm rheostat, actually called a potmeter or variable resistor arround here, with two 3.5W ys-tech fans. I had to put a 40mm 7v fan next to it as it got pretty hot at the slowest setting ...
the reason that people are using the lm317 version is that it is actually cheaper in parts, and is a more elegant solution.
|