new product: SchmartBoards - easy to solder Surface Mount prototyping break-out boards, even .4mm pitch, QFN and BGA.
Curious Inventor - Store: Red Knob
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in stock - price: $1.79
Red Knob
Red-knob

short description:

Fits on standard 1/4" potentiometer shafts with a set screw.

more information and instructions: