It features an onboard Sanguino clone using the ATMEGA644P with the ability of a ATMEGA1284 to be easily dropped in. Its four axes are powered by Pololu pin compatible stepper drivers.
The board features a developer friendly expansion port supporting I2C, SPI, UART, as well as a few ADC pins. All 14 expansion pins can be used as GPIO as well.
The board is designed to be flexible in the user’s power source availability, allowing for an ATX power supply to power the board, or the user can choose to install the voltage regulator kit for use with any power supply 7V-30V.
More information about this board can also be found on the Reprap Wiki