In 1994 John Weinel imported a number of these devices as curios from the Soviet Union. There were no instructions, and it wasn't clear exactly what it was or how it was used, but we guessed that it was a belay device that worked by passing a bight of rope through the long slot and around the belay carabiner. The rope could be held out of the V-slot by passing it over the notch at the top, and a fall could be stopped by letting the rope drop into the V slot. One thing we didn't like about this idea was that the sides of the V-slot were not rounded in any way, so this would be hard on the rope. A few years later Cassin introduced the Logic which is much like this device, and used in the manner described, so perhaps our guess wasn't far off.
If anyone has more information, please email me.
PlateBelay495.html/070304
©2007, Gary D. Storrick