This is a converter module USB-Serial TTL using the FTDI FT232RL IC. It can be used for general applications requiring a USB connection.
The module is very compact (just 25 x 12 x 8 mm). Terminal: 4-pin with 2.54mm pitch to implement a USB connection in your application easily and quickly. It is powered by the same USB port and allows you to set up, with a simple bridge, the voltage level used for the line TX-RX (3.3V or 5V).
This board has TX and RX LEDs, so you can see serial traffic on the LEDs to verify if the board is working.