ESP8266 series

USB to UART Chip: CP2102
Open-source, Interactive, Programmable, Low cost, Simple, Smart, WI-FI enabled
Integrated TR switch, balun, LNA, power amplifier and matching network
Integrated PLL, regulators, DCXO and power management units
Onboard USB to serial chip to easily program and upload codes from the Arduino IDE
Embeds logic level converter circuits
Has onboard 3.3V regulator to ensure enough power to function as your go-to WiFi chip!
Easy access to the GPIO pins for easy prototyping
ESP-12E Processor