it works as it costs, no more

Involvement:Expert (understands the inner workings) - Ownership:1 day to 1 week

It's cheap and it has a very simple design, so even if it fails you probably could fix it using a soldering iron.

Assembly quality is good, however power transistors are mounted to heatsink without a thermal gel.

It is very compact and thus suitable for other DIY projects.

No RPM alarm at all.

It is just a 3ch variable DC voltage power supply made around tl431 in smd case, powered up by three 772 transistors from NEC. No PWM inside, it is linear one!

Plugs wiring color is misleading, red is minus, white is plus, green is minus, black is another plus.

Well it works as expected, I have checked fan voltage from low to high and got 4.95 to 12.4 Volts while input voltage is about 12.5V DC.

However it is not suitable for power LEDs because it is not a PWM controller. You can dim the LEDs if they have 12V rating (12V=full brightness), however when using LEDs at half brightness all the extra voltage will just heat up the controller, so its efficiency is about 50% too.

Don't expect too much from this device. It just works as designed.