2 Pieces Adjustable LM2596S DC-DC Buck Converter Reduced Voltage Regulator Power Supply Module 36V 24V 12V to 5V 2A Voltage Stabilizer with Digital Voltmeter Display

These work fine - cheap and cheerful. One thing to note is the little blue trim pot takes about 25 turns (search BAOTER 3296 for the specs).I initially thought these were faulty as you literally have to make about 24 turns anti-clockwise before you see any voltage drop at all (I was trying to acheive 24v to 12v for a 3D printer fan). But I did get there in the end and it's pretty stable.It's probably worth turning the trim pot all the way down before you attach anything to them. I tested with a bench power supply and multi-meter and then hooked to an old PC fan before installation to be on the safe side. By default it was passing 24V straight out, so be aware of this to save your components!Some better instructions in the box would be helpful, the button lets you switch the display from input to output voltage (actually super handy for monitoring after installation). If you hold it down you appear to be able to access a +- 0.1 to 0.5 calibration option for both input and output voltages but that seems a bit of a redundant alongside the trim pot?

So far so good , great for the price paid

Overall I'm happy with the one that works but one was faulty which is annoying for a bit of a pricey converter. I only want to return 1 which is a bit annoying as amazon support is a bit of pain. The one that works is quite good however.

Unfortunately one of the two converters was not working messaged the seller and they replaced it very quickly for me other than that product works intended and having a read out and being able to switch the input and output reading with the click of a button is great.

These are fantastic bits of kit and are incredibly fascinating to me personally.Bought for modding a 12v and a 5v line of power to/around my 3D Printer so i could power some silent noctua 120mm fans to cool the mainboard and powersupply cus the stock fans sounded like a lawnmower next to your ear.Rotate the top screw of the potentiometer clockwise to boost the value of the output voltage, turn it counter-clockwise to reduce it.You need to turn it quite a lot to even see a value change on the display when reducing from my experience.

Took about 10 minutes each to fit. Just splice into your current fan cables & drop this inbetween. Be sure to set voltage first tho to prevent destroying your fans.. Work flawlessly.

First time plugged in - Vin from the board driving a 12v fan. Immediately let out the magic smoke - not on the buck but on my main board! Now I have to buy a new board :(

I haven't tried to fire these up yet.But the picture paints a thousand words.Package opened on delivery and the box also open.