This potentiometer is a two-in-one, good in a breadboard or with a panel. It's a log taper 10K ohm potentiometer, with a grippy shaft. 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 breadboard or perfboard. Once you're done prototyping, you can drill a hole into your project box and mount the potentiometer that way.
Potentiometers, or "pots" to electronics enthusiasts, are differentiated by how quickly their resistance changes. In linear pots, the amount of resistance changes in a direct pattern. If you turn or slide it halfway, its resistance will be halfway between its minimum and maximum settings. That's ideal for controlling lights or a fan, but not necessarily for audio controls. Volume controls have to cater to the human ear, which isn't linear. Instead, logarithmic pots like this one increase their resistance on a curve. At the halfway point volume will still be moderate, but it will increase sharply as you keep turning up the volume. This corresponds to how the human ear hears. Using a log pot therefore gives the effect that a setting of full volume on the control sounds twice as loud as a setting of half volume. A linear pot used as a volume control would give large apparent changes in loudness at low volume settings, with little apparent change over the rest of the control's range.
Once you're done prototyping, you can drill a hole into your project box and mount the potentiometer using the included washer and hex nut. We've got plenty of matching T18-splined knobs that you can pair up.