Knob for EC11 rotary encoder. Designed for a standard 6mm shaft, with a 20mm height. (The 20mm dimension is the most common). This is a variant of the Drippy shifter knob, which is a variant of the drippy bucket. I removed some of the cone detail to improve printing at this scale. 
The cone section is fragile - it doesn't need supports, but it may help.