The one picture on here has the Fet driver pedal in the same spot on the pedal board as the blurred pedal, but the blurred pedal is a different color. The pedal appears to say TTD on it, and it has the same basic color and style knobs as the BK Butler Tube driver.
The FET Driver could very well be the same pedal as the TTD, with just different cosmetics since the knobs are in the same spots on the pedal. No way of really knowing at this point from any information I have seen.
Judging by the name FET, I would think the FET driver has MOSFET's in it, and not tubes (someone else mentioned this).