CNC Shield Board: Version: 3.0 Color: Red Size (L*W*H): 68 x 53 x 18 mm Voltage: DC 12~36 V (At the moment only the DRV8825 drivers can handle up to 36V so please consider the operation voltage when powering the board.) Features: 1. Uses removable A4988 or DRV8825 compatible stepper drivers. 2. The extension board can be used for carving machine, 3 d printer driver expansion board 3. GRBL 0.8 compatible. (Open source firmware that runs on an UNO that turns G-code commands into stepper signals) 4. 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) 5. Compact design. Stepper Motors can be connected with 4 pin molex connectors or soldered in place. 6. Please note that this is an unassembled kit and Basic soldering skills are needed. A4988 Stepper Motor Driver: Color: Red Size (L*W*H): 20 x 15 x 10 mm 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 Five selectable step modes: full, 1/2, 1/4, 1/8 and 1/16 Features: 1. Mix with slow current decay modes. 2. Internal UVLO and Low RDS (On) Output. 3. Automatic current decay mode detection/selection. 4. Synchronous rectification for low power dissipation. 5. Warning: Connecting or disconnecting a stepper motor while the driver is powered can destroy the driver. Package includes: 1 x Engraver CNC Shield Board 4 x A4988 Stepper Motor Driver Note: Manual measuring, please allow 1 ~ 3 cm error, thank you.