It's a keyboard wrapped around a pole.

Rotate it, and you can play in a different key or mode.

Run your finger along it, and you've got a scale.

I suppose what makes this useful is the ability to find scales and
modes more easily, with one downside: you've got to play a pole. (See
the video if you're having a hard time imagining how that will look the
next time your band wants to play Secret Agent Man.) (via ektopia)