Nice quality knob which feels way better than it should at the price.
Aluminium outer, plastic inner. Skirted bottom obscures pot nut.
These knobs will push right down to the surface of the enclosure. If you have a fancy-pants paint job it would be wise to raise them slightly. A sliver of cardboard on top of the pot shaft before pressing the knob in place will do the trick.
Pot shaft size: 6.3mm splined
Diameter: 14mm at base
Fitting: Push fit
Price is per knob.