Review on HiLetgo Development Compatible Interface Arduino by Sirryan Bloodworth

But make sure you know how it works before you buy it. Most Pro Micro boards these days operate at 5V as required by this board. So if you want to connect this 5V board, you need level converter + 3v3 power regulator. Then it works perfectly. One of the downsides of this board is the lack of a jumper to power the USB port itself with a separate power supply (5V). Not all devices work properly with a 3.3V USB port.