This board is widely used for driver expansion board of engraving machines. There are a total 3 3-way slots for stepper motor driver modules (Model A4988 or Drv8825 - It sold separately at our store), and it can drive 3-way stepper motors each up to 2A. Each way stepper motor has two I/O ports and it means 6 I/O ports can manage 3 stepper motors. It is very convenient to operate.