Potentiometer 6Pin Shaft WH148 Amplifier Dual Stereo 20K
This potentiometer is a two-in-one: it's a log taper 20K ohm potentiometer, with a grippy shaft and it comes with an on-off switch. It's smooth and easy to turn, but not so loose that it will shift on its own. We like this one because the legs are 0.2" apart with pin-points, so you can plug it into a perf board. Note the spacing on the switch/pot pins is 0.2" so it won't work in a solderless breadboard as nicely unless you bend the switch pins out of the way. Once you're done prototyping, you can drill a hole into your project box and mount the potentiometer that way.