The ESP8266 WIFI module is a TTL "Serial to internet" module. This module makes it possible to connect easily with a Wi-Fi signal. This has hidden a lot of power in a small package, up to 1 A can be used for sending signals. 

Features
Voltage: 3.3V 
Supported types: 802.11 b / g / n 
Features: 
    Wi-Fi Direct (P2P), soft-AP 
    Integrated TCP / IP protocol stack 
Power: + 19.5dBm output in 802.11b mode 
Consumption when off: <10uA 
Communication: SDIO 1.1 / 2.0, SPI, UART 
Wake up time: <2ms 
Standby consumption: <1.0mW 

Type: ESP-07
 - 2x7 2 mm pads on the side 
 - Built-in ceramic antenna
 - IPEX connecor voor externe antenne
 - 9 GPIOs: GPOI 0 / 2 / 4 / 5 / 12 / 13 / 14 / 15 / 16
 - UART URXD / UTXD
 - RESET en CH_PD (powerdown)