When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
As johnZo said its for N.V.H. Noise/Vibration/Harshness. The cable is a safety catch. Some people remove them and see no additional vibrations, some people say they notice an increase if removed.
It is probably sized to dampen certain gear or u-joint resonant frequencies (ringing) at highway speeds. Probably won't make an impact for typical off-roading. It will work with the drag arm bushings to prevent resonant rotational vibrations of the axle.