PRUSSIAN BELT PLATE?

The buckle plate is out of my collection purchased in April 1996. I really do not know what this is and I have asked several advanced collectors and they have seen it before but no one seems to know what it was for. This buckle plate is 2 1/8" wide and the standard 1 7/8/" high. The reverse has two bars one on each end. So there you have it a neat whatever. Condition very good?