5 Pack LM2596 DC to DC Buck Converter 3.0-40V to 1.5-35V Power Supply Step Down Module

These work very well however the adjusting screw is a bit tricky. I turned it many times and no voltage change finally went the other way many turns and voila!

Works without problem, good quality

Using this to power (RPI) Octoprint from Creality 3D printer. Working great so far. I have only used 1 of the 5 (so far). Super easy to dial-in using a multimeter. I'm feeding 5.1 volts to RPI as I have read they like a little over that called for 5V.

Red digital display is kind of bright, you could consider a filter. Is nice, push button shoes both input, then toggle to output. 2 readings, very handy. I'll try to use it as charger for 18650 cells.

much better to both solder the connection wire to it and to regulate the output current than the more simple variants; it takes a few turns (around one turn per volt) to bring the current down from 24 to 5V for my use case in adding a wireless receiver to my PAR lights, but then they function very well

Overall good module, but please read the regulator chip datasheet before purchasing. At low output voltages, it has efficiency less than 75%. In my case, converting 12V to 3.3V at 2.5A overheats it in around 10 seconds (no heat sink added). Also, it drops over 170mV or 5% of output voltage, between idle and full 2.5A load.If you need high currents at low output voltages it makes sense to look for modern, high frequency synchronous regulators. This Simple Switcher family member is just too old and inefficient for such applications

you have to turn the screw several times and it begins to change output voltage

I thought my fans died in my Xbox 360, but turns out my fan mosfet died. Rather than running the fans at a constant 12v I used one of these to set the fans at 7v and now I have a much cooler and and much more tolerable sound level from my Xbox!