Round and round it goes, this nice round "scrubber" knob is the perfect mate to a rotary encoder.  It's got a wide 34.7mm diameter with a nice finger groove on its face so it's easy to turn with just one finger.  It works best with our rotary encoder, just snap it on, and away you go.

Please note: this knob won't work with our potentiometers which have T18 spline shafts! While rotary encoders look similar to potentiometers, they're actually very different.  Rotary encoders rotate all the way around continuously, which is why a knob like this is handy, you can twist it around very fast.

Does not come with a rotary encoder.

We also sell potentiometers in the Adafruit store and plenty of knobs to match if you're really just a knob fanatic.