ESP8266 NODEMCU V2

This is the famous NodeMCU which is based on ESP8266 WiFi SoC. This is version 3 and it is based on ESP-12E (An ESP8266 based WiFi module). NodeMCU is also an open-source firmware and development kit that helps you to prototype your IoT(Internet of Things) product within a few LUA script lines, and of course you can always program it with Arduino IDE.