esp8266 module.

USB to UART Chip: CH340G
Power input: 4.5V ~ 9V (10VMAX), USB-powered
Transfer rate: 110-460800bps
Support UART / GPIO data communication interface
Support Smart Link Smart Networking
Working temperature: -40°C ~ + 125°C
Drive Type: Dual high-power H-bridge
Don’t need to download resetting
A great set of tools to develop ESP8266
Flash size: 4MByte