Review on 🔌 DAOKI 5 PCS AC DC Power Supply Buck Converter: Step Down Module 12v 5v 3.3v 9v - Efficient Voltage Conversion Solution by Jason Mitts

No documentation, board mislabeled (thanks to others for pointing this out in advance), plugged in the first one (no load) and fie! Die in a microsecond. Yes, correctly connected. The second board puts out 3.3 volts (close enough), but the performance is completely unstable. It only powers the ESP8266-12F, but every few seconds the light will start flashing and the ESP will restart. Connected to an alternative power source, everything works. I measured the actual current draw with the power supply running and the peak draw is less than 150mA. All in all, don't buy this junk!