This module is a USB adapter/programmer for ESP8266 modules of type ESP-01.
It is conveniently fitted with a 2x4P 2.54mm female header to plug the ESP01 and run it right away.
A large 1000μF cap will help to get a steady 3.3V VCC from the USB bus
The module is based on the USB-UART bridge CH340 from WCH which is compatible with all platforms.
It can be also used as general USB to TTY serial adapter. (like famous FTDI adapter)
To be used as ESP-01 programmer, this module needs little tweaking. (connect GPIO0 to GND)
see this video on YouTube