Headphone hanger for < 0.75" knob

Designed to fit over a knob with a grab diameter of 0.75" and a neck diameter of 0.4". 

As always, PETG is ideal for functional prints, but PLA or anything else will work fine. Modeled in inches, so if it shows up tiny, scale up by 2540 to convert from mm to inches (Mainly an issue in Cura).