Module de carte d’extension WiFi série ESP8266 pour ArduinoESP8266 Serial WiFi Expansion Board Module for Arduino Description: Standard pin interface to achieve full compatibility with the pitch Arduino Uno, Mega and so on. (Unless the standard size Arduino, such as Nano, Mini) 3. 3V power supply using advanced chip (with the official expansion board power chip CC3000 same), so 3. 3V Arduino board provided more accurate, so ESP8266 as official CC3000 chip work as normal, there is no gap. It leads to a WiFi