The Arduino-Square includes a 3.3V Arduino Pro compatible microcomputer with easy access to the shield ports.
High Strength Magnetic Contacts.
Arduino Pro 328 – 3.3V / 8Mhz.
14 Digital I/O pins.
6 Analog input pins.
Arduino Shield Compatible connectors.
Reverse Polarity protection.
Resettable Fuse short protection.
The Software necessary to program the Arduino-Square can be found here http://arduino.cc/en/Main/Software
You will also need a serial-to-USB connector to connect the Arduino-Square to a PC.