The ESP 01 ESP8266 Serial WIFI Wireless Transceiver Module is ESP32-S2 general-purpose development board, based on ESP32-S2-WROVER, ESP32-S2-WROVER-I, ESP32-S2-WROOM or ESP32-S2-WROOM-I, with 4 MB flash and pin header.a self-contained SOC with integrated TCP/IP protocol stack that can give any microcontroller access to your WiFi network. The ESP8266 is capable of either hosting an application or offloading all Wi-Fi networking functions from another application processor. This module comes pre-programmed with an AT command set firmware, meaning, you can simply hook this up to your Arduino device and get about as much WiFi-ability as a WiFi Shield offers (and that’s just out of the box)! The ESP8266 module is an extremely cost-effective board with a huge, and ever-growing, community.