Features: Latest CNC Shield Version 3.0 for Arduino. GRBL 0.9 compatible (Open source firmware that runs on for Arduino that turns G-code commands into stepper signals). 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). Jumpers to set the Micro-Stepping for the stepper drivers. (Some drivers like the DRV8825 can do up to 1/32 micro-stepping). 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. Specifications: CNC Shield Board: PWM Spindle and direction pins 2 x End stops for each axis (6 in total) Coolant enable Uses removable A4988 or DRV8825 compatible stepper drivers 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.) A4988 Stepper Motor Driver: 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 1/16 Package List: 1 x CNC Shield Board 4 x A4988 Stepper Motor Driver 4 x Mini Heat Sink Note: Please note that this is an unassembled kit and Basic soldering skills are needed. 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) 1、Latest CNC Shield Version 3.0 for Arduino. 2、GRBL 0.9 compatible (Open source firmware that runs on for Arduino that turns G-code commands into stepper signals). 3、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). 4、Jumpers to set the Micro-Stepping for the stepper drivers. (Some drivers like the DRV8825 can do up to 1/32 micro-stepping). 5、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.