Steering Wheel Spinner Knob, also know as a "suicide knob" of "necker knob". I don't really recommend really using this during driving, since the fusion deposition modeling (filament 3D printing) the layers are prone to delamination and it could break during a crucial time during driving. Also, using this drivice for driving may be against some city ordinances.
The bushing is printed in NinjaFlex and the rest is in PLA at 50% infill.
The stl files may need to be reoriented for better printing. You shouldn't need any supports.
Assembly shown here.