Description: This board as a driver expansion board can be used for engraving machines and 3D printers. It has a total of four slots, which can drive four A4988 stepper motors. Each stepper motor only need two IO ports. In other words, six IO ports can well manage three stepper motors, which is very convenient to use. Features: This 3D printer accessories set meets most needs including CNC shield V3.0, A4988 stepper motor drivers. This board as a driver expansion board can be used for both engraving machines and 3D printers. It has 4 slots in total for A4988 stepper motor driver modules for driving 4 stepper motors. Each channel of stepper motor only needs 2 IO ports, which means 6 IO ports is sufficient to manage 3 stepper motors. This shield can make quick work for managing stepper motors in your project. PWM Spindle and direction pins,4-Axls support (X, Y, Z , A-Can duplicate X,Y,Z or do a full 4th axls with custom firmware using pins D12 and D13) Compact design. Stepper Motors can be connected with 4 pin connectors or soldered in place. Please note that this is an disassembled kit and basic soldering skills are needed. Specifications: MCU: ATmega328 Clock speed: 16 MHz Operating Voltage: 5 V I-I/O pin output current: 40 mA maximum 3.3 V output current: 150 mA maximum Digital I/O pins: 14 (including 6 with PWM capability) Analog input pins: 6 EEPROM: 1 kB Static RAM: 2 kB Flash memory: 32 kB A4988 Driver: Compatible Input Voltage: 7-15V DC Thermal Shutdown Circuitry: Yes Crossover-current Protection: Yes Ground Fault Protection: Yes Load Short-circuit Protection: Yes Compatible Logic Supply: 3.3V and 5 V Package Includes: 1 X CNC Shield V3 4 X A4988 Drivers 4 X Heat Sinks 1 X MEGA328P CH340G 1 X Pin Header 1 X USB Cable .