The Sim Innovations Air Manager software that is used to create custom 2D flight simulator panels is often controlled with a double encoder switch termed a “Knobster”.  The knobs that come with typical double encoders are small.  I designed these to be closer to the size of the knobs on Garmin GPS units.  They are not an exact match, just a more comfortable size.  These fit the dual encoder kit sold by Propwash Simulation with 3.5mm and 5.0mm shaft diameters.