GeeBat ESP8266 Serial WIFI Wireless Transceiver Module ESP-01 Support LWIP AP STA for Arduino UNO R3 Mega2560 Nano Pack of 2pcs ESP8266 is a highly integrated chip designed for the needs of a new connected world. It offers a complete and self-contained Wi-Fi networking solution, allowing it to either host the application or to offload all Wi-Fi networking functions from another application processor. 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. Link to view the technical details: https://nurdspace.nl/ESP8266#Translated_datasheet Some translated document: http://www.electrodragon.com/w/index.php?title=ESP8266&redirect=no Tutorial for ESP8266 Serial WiFi Module: https://www.zybuluo.com/kfihihc/note/31135