Worked great to reduce the brightness on my landscape light.

this worked great after I wired it correctly. It controls the power after the fan to ground, not going into the fan.

Will not work they are wired wrong

Good product that works as it should but they don't last long. I have had 2 burn out now (no continuity afterwords) with only a couple hours of use at most on them.

These speed controllers are a great deal at about $6 each (at the time of this review). A number of sellers are offering this identical controller for $10 - $15 apiece, so I figured these would be a good deal even if one or two burned out.As others have noted, the wiring is not explained correctly. I took two stars off ease of install because not everyone will know how to wire these correctly, or even realize that there is a problem with the directions. Wiring incorrectly can lead to the controller not working, or even to burning out the controller. The black wire of the controller connects to battery or power supply negative. The controller's red wire connects to battery or power supply positive. The positive side of the motor (or other load - I am using this to drive a Peltier cooler) should also connect to the red wire, while the negative side of the motor should be connected to the blue wire of the controller. Wired correctly, these should work well. All three of mine have done great so far.The first thing I did with mine was open them all up. After pulling the knob off, I unscrewed and removed the nuts and washers underneath it. Then I gently pried the heat sink out of the back end, one clip at a time. The insides all come out together. Here is what I found:The circuit is laid out reasonably, with components that should safely handle the rated workload. There are two electrolytic capacitors on the circuit board that are the most likely points of failure if things get hot. If that happens, I will replace the failed cap.The controller works by pulse width modulation, driven by a 555 timer. All three of my units used genuine TI NE555P precision timers that performed well. I checked the output on an oscilloscope and it looked pretty clean. There was only a little noise when driving a set of fans, and very little noise at all when driving a Peltier cooler.The 555 timer drives a P75NF758 mosfet, which is attached to the big heatsink at the end and carries all the current from the motor. If I were to push these controllers hard, I would consider replacing that heatsink with a fan, but I would still use the same transistor, since it can handle a lot more than this controller asks of it. All three of mine had the mosfet properly connected to the heatsink.I did note a couple of solder joints that looked cold and had a bit of resistance, so I touched them up real quick and they are fine now. I did not have any solder joints that failed toOverall, if I had paid $15 each for these from another seller, I would be annoyed with the work I had to do, but otherwise satisfied. At only 40% of that price, I am quite happy to touch up the soldering and sort the wiring out to end up with a solid controller. Since these open easily, I can service them myself in the event of a failure with cheap, readily-available parts, so I expect to have these in service for years to come.

Works great but as often happens with Chinese sellers, there are errors in the product listing. In this case, the error is in the wiring instructions! Here are correct wiring instructions:Blue wire is connected to motor-Red wire is connected to motor+ and power+Black wire is connected to power-

Controller wiring was not straight forward to figure out, but found information from another product.The controller worked well at first, but didn't even last two months and stopped workingNot very reliable, select a better alternative.

works well no problems to install