Features: Latest CNC Shield Version 3.0. GRBL 0.8c compatible. (Open source firmware that runs on a R3 Board 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) 2 x End stops for each axis (6 in total); Spindle enable and direction; Coolant enable. Uses removable Pololu A4988 compatible stepper drivers. (A4988, DRV8825 and others) Jumpers to set the Micro-Stepping for the stepper drivers. (Some drivers like the DRV8825 can do up to 1/32 micro-stepping ) Stepper Motors can be connected with 4 pin molex connectors or soldered in place. Runs on 12-36V DC. (At the moment only the Pololu DRV8825 drivers can handle up to 36V so please consider the operation voltage when powering the board.) Specifications: Package Size: 26.5 * 8.5 * 6.5cm / 10.4 * 3.3 * 2.6in Package Weight: 1200g / 42.3oz Packing List: 1 * CNC Shield V3.0 1 * R3 Board 4 * A4988 Driver 4 * Heat Sink 4 * 4401 Stepper Motor 4 * Motor Cable 1 * USB Cable