BB, A remotely adjustable shock preload is a way to compress or release the spring to accommodate more / less weight from luggage or 2nd passenger. It's accomplished by replacing the lock rings on the shock with a hydraulic sleeve that has a remote you turn in or out that forces fluid from the easy to get to remote through the hose into a hydraulic cylinder that compresses the spring more for more preload. rj
Looks like these:
http://www.ebay.com/itm/Progressive-...xXY4IC&vxp=mtr