Fuzzhugger Algal Bloom v2 - 12v or 18v ???

I can't find the card that came with the pedal. I remember it said something about being able to use either 12v or 18v for more headroom? I can't find anything online that backs this up other than the card that came with the pedal.
Can anyone confirm this, and what exactly does that mean, more 'headroom' ? Thanks
Can anyone confirm this, and what exactly does that mean, more 'headroom' ? Thanks
