Wolf: Alembic & Mesa, always a good choice! :-)
Mario: It's an old Morley Power wah fuzz (from 1975)
Original for guitar I think, but with an extreme wide sweep.
I only use it for wah/fuzz sounds (with a Big Muff), see
here I never tried it with normal bass sounds though...
I'll see if I can try it in the next couple of days, I'm sure you won't miss highs with this pedal :-)
If you want one of these old ones and don't need the fuzz, best would be to get the Power Wah (PWO)
They are a lot cheaper, have the same Wah sound and you can switch between Wah/volume pedal mode.