This was invented by Carl Brema c. 1935 and it was a popular dealer item in the 1930’s sold by Max Holden, Kanters, Abbott’s and others.
Effect: A very useful little device for forcing a particular color, number, or letter in connection with any trick. The cube is of polished ebonite, each side bearing a different color. It revolves on a small rod which passes through the center hole. A spectator holds the rod, spins the cube and when it stops, the desired color appears on the upper face of the cube. May be secretly changed in a jiffy for another color and repeated if desired.
(Notice: This does not come with any instructions.)( Post Source: martinsmagic.com - click for details )