4 axes systems are generally used as follows: 3 axes for x, y and z, and the 4th axis would turn the work piece being milled, or to turn the router/spindle for reach in specific applications. (4) NEMA 24 425 oz-in stepping motors(4) Drivers (3.0Amp 24-40 Volts, 1-1/64 microstepping)(1) 36v 8.8a Power Supply(1) Interface Board (USB or Parallel) Choose From 3 Interface Boards Parallel Board: Works with Mach3, Mach4, or Linux-CNC. Parallel Port and Parallel Cable Required on PC running a 32 bit OS. Software can be purchased from BuildYourCNC. Planet-CNC USB Board DISCONTINUED : Works with Planet-CNC Control Software ONLY. Mach3 USB Board: Works with Mach3 ONLY. Connects through standard USB port. Mach3 can be purchased from BuildYourCNC. If you are using the pokeys57CNC Controller, please view the videos on the product page for the Pokeys57CNC board below: https://buildyourcnc.com/products/electronicsandmotors-electronic-component-breakout-mach4-mach3-usb-ethernet-board?_pos=1&_sid=fc7b6afe6&_ss=r