The CNC Shield V3.0 is the perfect expansion shield to build an engraving machine, a 3D printer, or a mini CNC using your Arduino. It is designed as a shield and can plug on top of an Arduino requiring no external connections and wiring. There are 4 slots on the board for plugging in stepper motor drive modules which can drive 1 stepper motor each. Controlling each step stepper motor requires only two IO pins on the Arduino. Just insert this Arduino CNC Shield V3.0 onto an Arduino UNO, and install the GRBL firmware, and your DIY CNC engraving machine is ready to roll!