ESP8266 is a wifi SOC (system on a chip) produced by Espressif Systems. It is an highly integrated chip designed to provide full internet connectivity in a small package. This is a module based on ESP8266 chip.
Please see supplied pinout photo and schematics for connectivity details. There is a lot of online resources available for this module.
802.11 b / g / n
Wi-Fi Direct (P2P), soft-AP
Built-in TCP / IP protocol stack
Built-in TR switch, balun, LNA, power amplifier and matching network
Built-in PLL, voltage regulator and power management components
802.11b mode + 19.5dBm output power
Built-in temperature sensor
Support antenna diversity
off leakage current is less than 10uA
Built-in low-power 32-bit CPU: can double as an application processor
SDIO 2.0, SPI, UART
STBC, 1×1 MIMO, 2×1 MIMO
A-MPDU, A-MSDU aggregation and the 0.4 Within wake
2ms, connect and transfer data packets
standby power consumption of less than 1.0mW (DTIM3)
1 x ESP8266 Serial WIFI Wireless Transceiver Module.