CenryKay PWM DC Motor Speed Controller 12V-40V10A,Low Heat Generating with Reverse Polarity Protection, High Current Protection(2pcs)

Ordered a pair of these to use for PWM dimming of under-cabinet LED lights in the kitchen (two 'zones'). Installed into simple plastic boxes, spray painted black, with the knobs sticking out the front. Boxes aren't airtight, but they are fairly sealed, and they don't get hot from these things being in them. Also haven't been able to hear any kind of noise coming from these units, high pitched or otherwise. Easy to wire up and they just work.

Using these speed controllers to control a small high pressure water pump (12v, 3A). Wiring was straight forward and the board is nicely designed with standard components and appropriately labeled connection points. Product worked for 3 weeks and then one day started running at full power and would not accept any input from the dimmer switch. I contacted CenryKay and at first, through extremely broken English, I thought they were going to send me a replacement. I followed up a week later and apparently I misunderstood, they said the item was outside the 45 day warranty window and they would not provide any refunds, replacements, or further support. Fair enough, it was outside the 45 day warranty from when I purchased it. The other speed controller is still working but this product appears to be hit or miss from my experience. Purchase at your own risk.Excerpts from CenryKay communication:"it has violated the refund time set by Amazon, or you know that the product has a little defect in March, or you will not Use, at that time, you can report the consultation to us earlier, it is now beyond the prescribed time, we are sure that no refund can be made. Let us help you with technical issues later."...Ok"The last time you bought the product in the process of using the problem, we went to consult the technical staff, he gave the answer is that the part of the part is broken, maybe you can try another one to see if it is still that Question, thank you!"...My loss, you've been warned

First, it was the fuse and then the heatsink make the product last/durable.