CNC Shield Board: Latest Arduino CNC Shield Version 3.0 GRBL 0.9 compatible. (Open source firmware that runs on an Arduino UNO that turns G-code commands into stepper signals) PWM Spindle and direction pins 4-Axis support (X， Y， Z ， A-Can duplicate X，Y，Z or do a full 4th axis with custom firmware using pins D12 and D13) 2 x End stops for each axis (6 in total) Coolant enable Uses removable A4988 or DRV8825 compatible stepper drivers Jumpers to set the Micro-Stepping for the stepper drivers. (Some drivers like the DRV8825 can do up to 1/32 micro-stepping ) Compact design. Stepper Motors can be connected with 4 pin molex connectors or soldered in place. Runs on 12-36V DC. (At the moment only the DRV8825 drivers can handle up to 36V so please consider the operation voltage when powering the board.) Please note that this is an unassembled kit and Basic soldering skills are neededArduino UNO R3 Board: MCU: ATmega328 USB interface: ATmega16U2 Operating voltage: 5V Digital I/O pins: 14 (including 6 with PWM capability) Analog input pins: 6 I-I/O pin output current: 40mA max 3.3V output current: 150mA max Flash memory: 32 kB (0.5kB used by bootloader - included) Static RAM (SRAM): 2 kB EEPROM: 1 kB Clock speed: 16MHzA4988 Stepper Motor Driver: A4988 Stepper Motor Driver Board is a breakout board for Allegro’s A4988 DMOS Micro stepping Driver with Translator and Overcurrent Protection; please read the A4988 datasheet carefully before using this product. Low RDS (On) Output Automatic current decay mode detection / selection Mix with slow current decay modes Synchronous rectification for low power dissipation Internal UVLO Crossover-current protection 3.3 and 5 V compatible logic supply Thermal shutdown circuitry Ground fault protection Load short-circuit protection Five selectable step modes: full， 1/2， 1/4， 1/8 and 1/16Package Included: 1*CNC Shield Board 1*Arduino UNO R3 Board 4*A4988 Stepper Motor Driver Warning: Connecting or disconnecting a stepper motor while the driver is powered can destroy the driver. (More generally， rewiring anything while it is powered is asking for trouble).