This is a set of two gold-plated press-fit knobs for knurled-shaft 6mm potentiometers, with a distinctive ruby (red plastic) inset indicator. These knobs make a great, inexpensive finishing touch for your special build, and provide a nice "premium" look that plastic knobs just can't give. These knobs are metal with a plastic insert that fits over the pot shaft (there is no set screw). Please note the sizes below and make sure they will fit your intended usage.
Here are the sizes of these knobs:
Outside Diameter: .7505" / 19.1mm
Height: .672" / 17.1mm)
Inside (Shaft) Diameter: 6mm