Universal Nut

The nut has two ends. The threads on one end are much bigger than on the other. You show that the knob screws onto the small set of threads. Then you turn the whole thing around and screw the same knob onto the large screw threads! It doesn’t seem possible, but your viewers actually watch you do this, and then you can let them examine the universal nut and the knob. Includes instructions. Mild wear, else in very good condition.