This is a prototype rotary cipher machine made by the American inventor Edward Hebern. The black, white and silver-colored machine has a keyboard with letters arranged like those of a QUERTY keyboard, but no numbers or symbols. In the bottom row of the keyboard on the right are keys that read "Shift [/] Key" and "Space Code". The machine has no outer frame. In the back of the keyboard is an array of wires leading from a flat circuit board to a holder for a rotor. A second circuit board has wires that attach to prongs of a plug on the left side of the machine. This almost connects to 1991.0190.04. The single rotor has black bakelite rings on two sides with a cogged metal disc in between. It has the letters from A to Y around the rim, as well as a blank spot.