This expansion board as a driver expansion board, can be used for engraving machines, 3D printers, CNC. It is a total of four slots, can drive four A4988 stepper motor. Each road stepper motors only need two IO ports. In other words, six IO ports can be well managed three stepper motors. Very convenient to use. UNO for Arduino module IO port correspondence introduction: Not:There are four buttons on the remote control, and respectively correspond to the four data bits to the receiving board output pin D0, D1, D2, and D3 of. Press the buttons transmit signals, the corresponding data bit is output high. Package Includes:  One Piece new CNC shield v3 engraving machine 3D Printer  Module can be used with Arduino, Mbed, ARM or any other MCU SKU: PGI-0012202 Category: 3D Accessories