Here is what Mike says...  
'The Worm Drive returns. It's still a one knob, single transistor Fuzz but this time with an MPSA13 transistor and BAT41 diode (for those that care) in its mutant Wormy tummy. This change gives a more Fuzz / Distortion vibe. The mini pedal format makes it super versatile and pedal board friendly... oh, and with hand painted graphics, it looks as good as it sounds. Give a Worm a good home this Christmas.'