HiLetgo ESP8266 ESP-01 Serial Wifi Wireless Transceiver Module - Arduino Compatible Add WiFi capabilities to your Arduino or other microcontroller project WiFi serial transceiver module, based on ESP8266 SoC Interface using simple AT commands over serial/uart Integrated TCP/IP protocol stack. 802.11 b/g/n, SDIO 1.1/2.0, SPI, UART, Wi-Fi Direct (P2P), soft-AP Newer version with two LEDs, red and blue, and the GPIOs connected