CNC Shield Board: (Learn more information pls go to ASIN: B0157ZZ28M) 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.) A4988 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 1/16 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). Package includes: 1x CNC Shield Board 4x A4988 Stepper Motor Driver