spectrum stepper motor cables give your motors the cable length they need to run the distance of your slider while using them with the eMotimo spectrum. This is great if you need to mount your motor to one end of your slider. Pick up the length that matches your slider.
Please note, these cables typically won't work with other vendor's motors. If you have a stepper motor from another vendor, modification may be required. Why not? eMotimo motors and the way we drive them hasn't changed in over 5 years. As other manufactures began to offer similar motors over the past two years, either through mistakes or deliberate decisions, they have created motors that aren't wired in a compatible way.