Vintage Set of 2 "revolver" Display Cases Made by Berg Madison WI in Milwaukee, Wisconsin For Sale

Go back more than 60 years to Mr. B. L. Berg, of Madison, Wisconsin. In xxxx, the concept of a showcase with multiple shelves that could be rotated to position the shelf for viewing was first developed by Ben Berg, for use in his store in Madison. Berg tested his idea for the next several years building some crude but promising prototypes. By xxxx Berg had refined his design and the first hand made models were put into service in the Berg Sporting Goods Store in Madison.
Berg's cases were more successful than he ever imagined. Tied flies and fishing lures were displayed in his first models. These very small and traditionally difficult to merchandise flies were perfect for his "revolver" showcase as his customers called it. The customer was invited to operate a switch which caused the display to rotate forward or in reverse while selecting an item. Multiple trays which revolved in a vertical motion held over 400 different varieties of flies and lures. The merchandise was in perfect order, safe from pilferage yet readily view able by the customer. Simultaneously the product was easily accessible to the store clerk.
I am asking $xxxx.00 for the two cases.
You can visit the store and see how Great they operate at:
Milwaukee Thrift
xxxx S, Howell Avenue
Milwaukee, WI xxxx7.
Between 11am and 6pm