Dimensions Upper Knob:
Height: 10 mm
Outside Diameter: 15.3 mm
Knob Inner Diameter: 6 mm
Inner Diameter Spacer: 4 mm

Dimensions Lower Knob:
Height: 9 mm
Outside Diameter: 19.2 mm
Knob Inner Diameter: 8 mm
Inner Diameter Spacer Sleeve: 6 mm