For the DIY'r, these stepper motors allow you to drive a dolly or other custom motion control accessory through the M3/M4 ports on the side of your spectrum.
The 5:1, 14:1 and 27:1 Motor has:
Efficient Planetary Gear Drive
8 mm mounting shaft
The Direct Drive Motor has:
5 mm mounting shaft
Both Motors have a short lead spectrum connector with strain relief. This allows you to plug into the AUX port of the spectrum with no soldering or crimping.
Extension cables are not included and are needed.