Cactus Micro Rev2 Arduino compatible plus esp8266 - Seeed Studio

Cactus Micro is our integrated developement board, we have mixed Arduino with WI-FI into a single board. It is targeted for makers to develop low power Internet-Of-Things (IoT) projects quickly and easily.
The revision 2 use hardware serial port Serial1 as default option. It also Added some jumpers for connect esp8266 GPIO. For some usage such as I2C.
What makes it special?
Cactus Micro is tiny size Arduino compatible dev board. It's built-in a esp8266 module (esp-03).
Features?
Built-in ESP8266 WIFI module
ATmega32U4 running at 3.3V/8MHz
Supported under Arduino IDE 1.0.6
On-Board micro-USB connector for programming
4 x 10-bit ADC pins
12 x Digital I/Os (5 are PWM capable)
Rx and Tx Hardware Serial Connections
Getting Started
Open Arduino IDE and choose board "LilyPad USB" to start playing with your Cactus Micro in just a few easy steps.
How it works
The ESP8266 chip communicates with ATMega32U4 through the hardware serial port Serial1.
The pin 13 is connected to pin CH_PD of ESP8266. Put the pin 13 high to enable ESP8266 chip.
Part List:
1 xCactus Micro
1x ESP8266 module (ESP-03)
1x Male headers (Not soldering)