Don't let a jellyfish sting ruin your day at the beach. If you swim, snorkel, surf, or scuba dive, you've certainly come in contact with a jellyfish before. The sting can be excruciating and can be nearly impossible to stop without immediate first aid. That's when Smithwick's StingMate comes to the rescue. StingMate is a vinegar based gel that is infused with menthol to cool the sting area.