Perfect Companion for ESP8266: a USB-to-serial module that converts the USB interface to a serial port suitable for ESP8266
Using CH340 Serial Chip: more stable performance, powerful compatibility, support all Windows system
The main purpose is to connect ESP8266 and the computer PC via the serial port
Little Tip: you need to solder a pushbutton across the ground and a GPIO0 pin. Only need to hold the button for a few seconds as you plug it into a USB port then you can let go and the ESP is in program mode
For more information on this device, you can google “All in one ESP-01 to USB converter” The first result is a page on the esp8266 wiki with great information. They have details on getting into programming mode, and links for the CH340 drivers if you need them
High-speed CPU frequency and can be used as a serial port WIFI