Well... it's a non-pickup EMG.

THE EMG BOX!!! Active cardboard is much better than passive!

Oh... and a funny looking knob to put on my Kramer.

It's an EMG AB (afterburner). Adds 20db of volume when full and in use. Basicaly it's a boost pedal built into your guitar. Doesn't really add much colouration. Makes it louder. Boosts from rock into metal. It's good. (that's the sad excuse for a review, and you have pics right up there)
Interesting. Would that knob suffice as a solo boost? Perhaps a mid boost knob would be more suitable. Either way cool stuff dude