Originally made to fit an American Fender Stratocaster.  The knob fits the standard 6mm slit splined potentiometer shaft.  Made with a bone colored casting resin and antiqued with an oil based black paint (both made in USA).

The hole is reamed to 15/64 (5.95mm) to fit 6mm splined shaft.  BawdyPartz also mades these with 1/4″ hole and set screw for a more universal fit.

Skull Measurements

11/16″   Base to Forehead
1-1/4″   Chin to Crown
3/4″   Cheek to Cheek