This is WEMOS CH340G Breakout 5V 3.3V USB to Serial Module. Fine workmanship, long life span.Mini size, easy to install.

Features: 

Made of premium material, it is reliable and safe to use.

Use CH340G with stable performance.

Driver: 1. CH340G USB to UART driver

RTS: 1. Connect R/C port to RTS, it can flash ESP8266 module(such as: ESP-01 02 … 12F)

CTS: 1. Connect R/C port to CTS, it can flash for Arduino boards(such as: for Arduino pro mini)

Package Includes:

1 x WEMOS CH340G Breakout 5V 3.3V USB to Serial Module