All control knobs are poured, drilled, tapped and painted with a white line by hand at POM AUDIO DESIGN :

Control knob MakingKnob makingLine Painting

All Control knobs on the FAIRCHILD 670 mkI and mkII can be adjusted as the original 1950s ones, all you need is a metric M2 Allen-Key :

M2 Allan Key

(Supplied with every FAIRCHILD670 mkI and mkII)