Sort of a great device? I mean it works out of the box, BUT you'll struggle figuring out how to configure it. I was able to access the temperature amplitude and output power settings, but was not able to save those settings in any way. Others have mentioned you have to wait for the settings to save without pressing anything, others suggested longpressing the single button to save. In either case I was not able to achieve any configuration at all. All behaviour prior or after configuartion exhibited same behaviour under any temperatures the senor read. AGAIN, BUT, it's sort of ok, because the default settings are pretty good. In my situation I installed two noctua fans with these controllers into my old PowerMac G3 B&W and it's dead silent and well cooled.
Aw. I was hoping that it would work with 3-pin fans, but it sadly doesn't. Of course, no blame to the seller as this quality product was quickly shipped and delivered.