AC Motor Variable Speed Controller for Router Fan Electric Motor Rheostat, SCR Voltage Controller 120V 220V 15A 4000W Max

Using this to control electric heating mantles for lab glassware, very pleased! So far the biggest load I've hooked up to it is 350 watts but it handled that no problem. There is no hum or coil whine, the box does not get hot, and it gives reasonably fine control over resistive heating elements. As others have mentioned, the range of the dial is a little bit compressed, e.g. my copy doesn't put any power out with my loads until around the 12-13 mark on the dial, but if you add an inline watt meter you can get exactly the right amount of power without any fuss. This is a great value to control simple electronics.

This worked fine for reducing the speed of my 2 fans. I used a power strip in the box and plugged the fans in power strip.

Definitely not 4000 watts as I had a 1650 watt item plugged into it. I lost control to the dial after about 10 minutes and then I shut off the power button and it didn’t shut off. It started smoking and it could have caught fire. The cord isn’t even rated for 1200 watts. I definitely would NOT recommend for anything above 1000 watts.

Visually it's phenomenal... Layout is phenomenal.. ease of use is phenomenal.. but they clearly don't test them or check that wires are undamaged. First one had 2 damaged wires (which caused a short), a bad solder connection that fell apart and the voltage adjustment dial stopped working after 20 min... Replacement unit's dial lasted 5 min and quickly became too hot to touch. Great design but that doesn't matter if it doesn't work

I mounted this on a 36-inch utility floor fan. Excellent for reducing the speed so it doesn't overpower you while you are working. I hardly ever used the fan before I got this.