This hydrophobic sweatband collects excess sweat through capillary action as the fibres have been microscopically woven into teeny little Tesla valvular conduits drawing moisture in a single direction towards the back of one's head to be disposed of by gravity in whichever manner one chooses.
You
could water your plants with your spent electrolytes when you get home from a jog.
You could solar-still the liquid and re-ingest it in survival situations.
Ward off attackers with a well placed stream or eight.
Put out small fires at whim.
There's just so many uses.