Strange DEC heavyweight.

I have a paperweight of rough dimension 20" by 20" by 6", having a base with a flange to secure the paperweight to some other device, a motor about 6" in diameter protruding from the outside of the base, the base being about 2" thick, with a top cover about 5" thick. The base is grey metal, perhaps aluminum, while the top cover is gold in color. Now, this item has a layer of what appears to be a foam material which provides a seal between the base and top cover, and out of one side come five cables, four with ribbon cable and end connectors marked W033, and the fifth with a round cable and an unmarked connector. This device is a DEC product, having the appropriate lable, with the following information: RS11 WF6581 Please, can any of your tell me what this item is, and how it may be used. I can tell you that it weighs between 70 and 100 lbs, as judged by my own strength. William R. Buckley