Paradise 10 Hard Drive for Mac 128K

Anybody have any experience with a Paradise 10 or 20 hard disk drive from the mid-80s? Interesting eBay auction recently included one:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170499090200

There's very little detail about it, and none of the pictures appear to show it plugged in. But from what I can see, it only has two cables, a power cable and a port connection cable. I have some literature about this, but not much more than advertising blurbs, not much about functionality.