About ESP8266 ESP8266 has powerful on-board processing and storage capabilities that allow it to be integrated with the sensors and other application specific devices through its GPIOs with minimal development up-front and minimal loading during runtime. Its high degree of on-chip integration allows for minimal external circuitry, and the entire solution, including front-end module, is designed to occupy minimal PCB area. USB to Serial Adapter Using CH340 serial interface chip, stable performance and good compatibility. 1000uF polymer capacitor ensures power supply so WiFi module will not crash because of power problems. Using 3255 crystal oscillator, which can enhance working stability of serial port. Used for connecting ESP8266 and computer via serial port. ESP-01 Serial/UART baud rate: 115200 bps Input power: 3.3V I/O voltage tolerance: 3.6V Max Flash Memory Size: 512KB Support 3 modes: AP, STA, AP + STA WiFi security modes: WPA, WPA2 The link have many optional items, please choose the product you need, thanks