The rotaries and crossfader in the middle section are plastic, but feel solid enough.

ENGADGET: PDJ Portable Disc Jockey is a complete DJ system that fits in your pocket, we go hands-on (video)

The mixer section has rotaries for volume, FX and additional functions (more on this later).

ENGADGET

Numark has also added touch functionality to a lot of the rotaries.

ENGADGET

As for the touch-enabled rotaries?

ENGADGET: Numark NS7 II Serato DJ controller hands-on (video)