HiLetgo 10pcs AMS1117-3.3 DC-DC Step-Down Power Module AMS1117-3.3V Buck Module LDO 800MA

Good product

This is the same linear voltage regulator that is used on the NodeMCU board to power the ESP8266 with 3.3V from Vin. I use this little board to power electronics that need to communicate with the ESP8266 at 3.3V if they are placed in another enclosure far apart or if the current requirements are too high. The PCB construction is sturdy and the form factor is small enough. The on-board LED gives good feedback so you know when the unit is on, but you may want to remove it if you're running off a battery and want to save power.

Nice little step down modules for USB 5v to 3.3v DC

Bueno

This is described in the ad as a buck regulator. Looking at the mfg. data sheet, this is untrue. This is a linear 3-pin regulator, not a buck regulator. If you look at the picture you will not see a coil, needed for a buck regulator. That being said, these little guys work great. I have a project using an Esp32S3 , display and an I2S DAC amplifier. The 3.3v regulator was not up to the challenge. Audio output would sometimes cause a reset. I put the regulator between the dev boards 5v line and the audio boards 3.3v input. Problem solved.